Cable Television

DOCUMENT RESUME

ED 082 512 EM 011 485

TITLE Technology of Cable Television. INSTITUTION Cable Television Information Center, Washington, D.C. SPONS AGENCY Ford Foundation, New York, N.Y.; John and Mary R. Markle Foundation, New York, N.Y. PUB DATE 73 NOTE 33p. AVAILABLE FROM Cable Television Information Center, The Urban Institute, 2100 M Street, N.W., Washington, D.C. 20037

EDRS PRICE MF-$0.65 HC Not Available from EDRS. DESCRIPTORS *Cable Television; *Community Antennas; Community Change; Community Leaders; *Community Planning; Community Programs; *Decision Making; Local Issues; Social Change; *Technological Advancement; Telecommunication; Television

ABSTRACT The technology of cable television (CATV) is one area in which local community officials need to develop knowledge so that their decisions about the structure of CATV within the community will be informed. Thus, this paper is designed to familiarize local decision makers with the technological aspects of cable communications, to isolate specific questions which local officials must consider as they plan for CATV in their communities, and to note and explain options available to franchising authorities in dealing with those questions. Section One of the report describes cable technology past, present and future; the second section considers issues involved in systems design technical performance standard, and the implementation of future technology. (Author/SR)

5 Cable Television Information Center Technology of Cable Television the urban institute "PERMISSION TO REPRODUCE THIS COPYRIGHTED MATERIAL BY MICRO. FICHE ONLY HAS BEEN GRANTED BY

CebleTeletk-sioIn(crwmi,9AnIty TO ERIC AND ORGANIZATIONS OPERAT NO UNDER AGREEMENTS WITH THE NA TIONAL INSTITUTE OF EDUCATION. FURTHER REPRODUCTION OUTSIDE THE ERIC SYSTEM REQUIRES PERMIS SION OF THE COPYRIGHT OWNER."

Copyright © 1973 by Cable Television Informa- tion Center, The Urban Institute. All rights reserved. No part of this document may be used or reproduced in any manner whatsoever without written permission except in the case of brief quotations embodied in critical articles and reviews. For information address: Cable Television Information Center, 2100 M Street, N.W., Washington,D.C. 20037. Att: Information Group. TECHNOLOGY OF CABLE TELEVISION

U.S. DEPARTMENT OF HEALTH, EDUCATION & WELFARE NATIONAL INSTITUTE OF EDUCATION THIS DOCUMENT HAS BEEN REPRO DUCED EXACTLY AS RECEIVED FROM THE PERSON OR ORGANIZATION ORIGIN. ATING IT. POINTS OF VIEW OR OPINIONS STATED DO NOT NECESSARILY REPRE SENT OFFICIAL NATIONAL INSTITUTE OF EDUCATION POSITION OR POLICY.

CABLE TELEVISION INFORMATION CENTER The Urban Institute 2100 M Street, N.W., Washington, D.C. 20037 PREFACE

This document was prepared by the Cable Television Information Center under grants from the Ford Foundation and the John and Mary R. Markle Foundation to The Urban Institute. The primary function of the center's publications program is to provide policy makers in local and state governments with the information and analytical tools required to arrive at optimum policies and procedures for the development -of cable television in the public interest. ACKNOWLEDGMENTS

The center is indebted to The MITRE Corporation, McLean, Virginia. CONTENTS

INTRODUCTION 7

I. TECHNOLOGY OF CABLE TELEVISION 7

A.Traditional CATV Systems 7

B. Modern Cable TelevisionI 11

C. Broadband Communications Cable's Future 14

II.MAJOR ISSUES FOR FRANCHISING AUTHORITIES 19

A. Design Decisions 19

B. Technical Standards 29

C. Role in the Evolution of Cable Technology 32

III. CONCLUSION 33 7

INTRODUCTION The second and third goals are treated in Section II. The issues involved in system design, technical performance standards, and the implementation Cable television's entrance into a community of future technology are examined from the per- poses special problems for local officials. spective of the local public official faced with deci- Although it is an opportunity to determine how sions. the community wants to regulate a new service a new medium of communication itis an TECHNOLOGY OF opportunity often overlooked. Taking full advan- tage of the opportunity usually requires a basic CABLE TELEVISION educational effort so that decisions can be made on the basis of a working knowledge of how cable This chapter explains how traditional commun- television operates, how local citizens can make ity antenna TV (CATV) systems work, discusses use of it, and what decisions local authorities can the technical characteristics of modern cable tele- take responsibility for making. vision, and, examines problems and prospects for The technology of cable television is one area broadband cable .communications -4-- the in which local officials need to develop the know- advanced systems that exist now only in pro- ledge on which to base their decisions. It is impor- totype. tant that local decision makers understalnd cable television technology for several reasons. First, A. Traditional CATV Systems because a cable television system's technical design importantly influences its social and enter- Cable television began by providing a service tainment usefulness, systems should be planned which extended the range of broadcast television with thorough consideration of local demog- stations, or, differently put, brought broadcast TV raphic, social, and political characteristics and the to those who could not otherwise receive it. service demands which these characteristics may Broadcast television service is most attractive make on that system. Second, since there must economically when the area it covers (a radius be reliable delivery of high quality television sign- of roughly 35 miles around the transmitter) is heav- alsif cable is to perform adequately any of its ily populated. The reason is that broadcast televi- existing or projected functions, franchising sion station revenur ;s derived almost entirely authorities should establish technical standards from advertisers, ,,t:hu pay for "time" on an against which the performance Of a system can amount-per-viewer basis. The more viewers a TV be measured. Third, because cable technology station reaches, the more it can charge for audi- will continue to grow in sophistication, local offi- ence time. cials will want to develop regulations that will per- However, the ability to saturate an area, while mit their community to accommodate changes in implortantitO the station owner and advertiser, that technology. poses certain disadvantages. Once a television sta- This publication has three goals: tion begins to broadcast, the same assigned fre- To familiarize local decision makers with the quency, or channel number, cannot be used by any other broadcaster within 200 miles; the two technological aspects of cable communications; To isolate specific questions which local offi- signals will interfere with one another. Further, a local station broadcasting on a VHF cials must consideras theyplan for cable television (broadcast channels 2-13) channel adjacent to the in their communities; and . channel of another station within 100 miles will To note and explain, where applicable, options available to franchising authorities in dealing with interfere with the distant signal. The 12 VHF channels are not all adjacent to one another. But inter- those questions. ference problems among those that are, limit the

Section 1 of this report describes cable number of VHF broadcast television stations a technologythe first goal of this paper. The basic viewer can receive to seven.' Table 1 illustrates components of a cable television system are this problem in Baltimore and Washington. explained both in the historical context of how In practice, the economics of broadcast televi- most systems were built before governments and sion usually, limit the number of stations even citizens were aware of cable's potential impor- further. Small cities and towns simply do not have tance, and how systems are being planned today. 'Any of two TV channels are considered adjacent when their Discussion is also directed to the role of cable video carriers are 6 MHz apart. Channels 4-5 and 6-7 are the communications in the future. only non-adjacent channels. 8

enough viewers to support more than one or two Hence, the number of stations that can be carried stations. Itis this economic limit which has is limited by the number of cables one can afford retarded the development of UHF television to lay not by any fundamental restvictions as once thought to be the key to diversity and local- in broadcasting. ism in television service because of the number Finally, since the cable protects signals it carries of channels. from ocAside interference, it potentially can CATV systems grew in towns whose citizens deriver i1 !1;;,ter quality signals than those received received either poor reception or no signals at off-thcx. all. These systems typically provided one to five A CA,TV system consists of three components: broadcast TV signals to subscribers, and thus were A headend, or control center not radically different from broadcast television A distribution system a network of cables service. which delivEr signals to subscribers' homes However, cable TV systems do use coaxial cable A subscriber terminal in this case, merely as a medium for delivering television signals, with the subscriber's television set. characteristics different from broadcast TV. A single cable can carry as ,many as 40 television HEADEND signals that do not interfere with each other from one point to another. Further, because signals car- The headend includes an electronic control ried by cable'Veak" only slightly from the inside center (sec.. Figure 1), which may or may not be of the cable, q.re frequencies used in one cable housed near e 100 to 500 foot tower with a sensitive can be used again in another cable next to it. antenna mouir:ed on it for each broadcast televi-

Table 1. TV Channel Allocations (VHF)

CHANNEL BALTIMORE WASHINGTON OTHER

2 WMAR-TV

Harrisonburg, Va. 3 and Philadelphia, Pa.

4 WRC-TV 5 WTTG Richmond, Va. and 6 Philadelphia, Pa.

7 WMAL-TV

Richmond, Va. and Lancaster, Pa.

9 s WTOP-TV Altoona and Phila- 10 delphia, Pa. 11_..WBAL-TV Richmond, Va., 12 ), Wilmington, Del. and Lynchburg, Va.

But separate cable systems in Baltimore and Washington could each carry a full twelve channels (2 through 13) without the possibility of major interference.

Source: Charles Tate, ed., Cable Television In the Cities: ComniUnity Control, Public Access and Minority Ownership (Washington: The Urban Institute, 1971), p. 9. 9

DISTRIBUTION SYSTEM

The process of transporting signals trom the headend to the subscriber is commonly referred to as "downstream" communication; the traditional cable system,is capable of communication in the downstream direction only. The distribution system for one-way communication consists of a coaxial cable and the electronics necessary to transport signals from the headend to the subscriber. The basic element is a coaxial cable; the cable consists of an inner conductor, generally ,-! made of copper or copper-clad aluminum sur- a rounded by an insulator (such as extruded foam Figure 1. Control Center for a Cable Television System Headend. polystyrene or extruded foam polyethylene) which is in turn enclosed by an outer conductor, sion signal received by the system (see Figure 2). typically aluminum (see Figure 3). Coaxial cables The antenna is sited to provide the best available used by the cable television industry range in signal reception. Each received television signal diameter from one-quarter to one inch. passes through a processing amplifier, which separates the sound and picture components, and adjusts the signal levels to prevent a strong signal from one channel from overpowering another on plastic sheathing an adjacent channel (as often happens in broadcast television): Thus, all 12 VHF channels can be used. The amplifier then reassembles the picture and sound signals for transmission th roughout the distribution system. \1 UHF signals are broadcast at levels above the range of frequencies which can be transmitted outer conductor via cable electronics. In a cable system which also carries UHF television signals, the headend plasm foim includes electronic equipment to convertUHF signals to unused VHF channel frequencies within inner conductor the cable system spectrum. Figure 3. Coaxial Cable.

The distribution network, or "plant," is divided into two portions, trunk lines and feeder lines. Trunk lines, which are constructed of one-half to three-quarter inch coaxial cable, are the major arteries of the cable system. They transport the signals from the headend to the extremities of the cable system. Feeder lines, which are connected to the trunk lines, carry signals past each home. In a typical distribution plant, there is two to five times as much feeder cable as trunk cable. Although individual trunk lines are longer than feeder lines, there are a far greater number of feeder lines. Both the trunk line and feeder lines employ electronic amplifiers which are installed at specific intervals to boost the cable signal, as shown in Figure 4. Feeder lines are connected to the trunk Figure 2. Antennas and Tower for a Cable Television System lines by an electronic device called a bridger Headend. amplifier. This amplifier draws signal power from 10 cable and amplifiers introduce random electronic impulses into the television signal as it travels through the distribution system. These impulses are called "noise," and appear on the television screen as snow. Since each amplifier boosts both the signal and the noise, there is a limit to the total number of amplifiers which can be attached to a length of cable. Current design permits signals to be processed by 18 to 25 trunk amplifiers in a row ("cascade") before the amount of snow becomes objectionable. The distance between amplifiers depends upon the degree to which each amplifier boosts the signal. The amount of boost is limited because at high signal output, the amplifier produces other kinds of signal degradation. These degradations, called intermodulation and cross-modulation distortion, appear on the television set as moving bars or stripes. Trunk cable amplifiers are operated at low power levels to minimize amplifier-produced degradation. In practice, the distance between trunk amplifiers is about 2,000 feel. Thus, in combination, the amplifier cascade limit and the max- Figure 4. Cable and Amplifier. imum distance between amplifiers defines the maximum distance for trunk cable to be 7 to 10 the trunk for further distribution, and protects the miles. trunk lines from electronic disturbance in the Feeder cable amplifiers (sometimes called line feeder lines. extenders) feed signals to the subscriber. They Subscribers' television sets are connected to the are operated at higher power levels than trunk feeder lines with. a subscriber "drop" line. The amplifiers in order to permit more subscribers to subscriber drop consists of a tap at the feeder, be fed from a single amplifier. Since the feeder the drop cable (typically one-quarter inch diame- amplifiers are operated at higher power levels than ter cable), and a room wall plate connector. A the trunk amplifiers, the number of cascaded short length of coaxial cable runs from the wall feeder amplifiers is normally limited by (1:stortion plate and is connected to the antenna terminals considerations to three. The distance between of the television set via a matching transformer. feeder amplifiers is less than between trunk An understanding of the electronics in the dis- amplifiers, because the large number of sub- tribution system is helpful in making decisions scribers drain signal from the feeder cable. In prac- about system layout and capacity. Two problems in the electronic operation of cable system distribution limit the size of the geog- i» III)) I raphical area a single cable system can serve. They 4'4 are termed attenuation and distortion. Coaxial cable attenuates, or weakens, a signal it carries. As a television signal, flows through cable, the signal strength, or power of the television signal, diminishes; a typical coaxial cable trunk line has its signal reduced to 1/100 of its original strength for approximately every 2,000 feet of cable. The reduction of signal strength becomes perceptible to the viewer as a 'snowy picture. To counteract this attenuation, amplifiers are connected to the coaxial cable to boost signal strength. Unfortunately, theamplifiers themselves Figure 5. Cable Distribution Network for a Cable Television cause the second problem distortion. Both System. lice, feeder cable extends no more than 4,000 feet MHz from the trunk, and often less. Figure 5 illustrate -S06 a typical trunk and feeder network.

SUBSCRIBER TERMINAL UHF tekvision (channels 14 to 70) < "Subscriber terminal" is a term more appropriate to the description of advanced rather than contemporary systems. Here, in the case of traditional CATV systems, the term refers simply to 600 the subscriber's televisionreceiver;in an advanced cable system it would consist of a television receiver in addition to other facilities, and would he capable of two-way communication and 500 other services. The standard television receiver is capable of receiving two bands of television broadcast frequencies: VHF and UHF. Unfortunately, as Figure 400 6 illustrates, present cable electronics design fre- Aeronautical and mobile.< quencies are not broad enough to encompass UHF communications television frequencies. System operators deal with this problem partially, by converting UHF signals 300 at the headend to unused VHF channels. But while the operators can deliver as many as 35 channels

to subscribers' homes, the standard television - )16 I VHF television I I I I 200 receiver can receive no more than 12 of those (channels 7 to 13) channels.' 174 The standard receiver is equipped with elec- Aeronautical and mobile Approxin ate range communications of fret uencies tronic circuits that enable it to tune and receive 108 on cable broadcast signals. These circuits are not necessary FM radio 100 VHF television 88 I for cable reception and may introduce unwanted (channels 2 to 6) I broadcast signals that will interfere with cable,sys- 54 Mobile communications 1101111111 terns. This problem can be reduced if the cable 30 operator is permitted to modify the-Inside of the 3 television receiver or connect the cable directly to the tuner. Figure 6. Television Frequency Spectrum A more practical solution is the development small to support a television station, or too far of a special cable receiver, designed to receive from cities that did have stations. Traditional CATV all 35 channels from the cable. Research and was essentially a retransmission service; but as development is taking place, but as yet there is the cable industry flourished, traditional systems no such cable receiveron the market. In the mean- provided the economic base for the further time, other arrangements have been devised to development of cable television technology. increase capacity. These arrangements will be dis- Traditional cable television systems developed cussed later in more detail. in areas where broadcast television is poor. Today, systems are built in areas where broadcast television service is available. Consequently, the pro- B. Modern Cable Television vision of standard television signals will not be enough, and cable operators in urban environ- Traditional cable television was developed to ments will have to provide new and more diverse provide television service to communities too services. The result will be a more technically complex cable system. 'Although cable electronics permit transmission of 40 television channels simultaneously, at present no manufacturer has 1. Headends are becoming more sophisticated, designed a system that delivers more than 35 channels to subscriber's': Thus, although the electronic capacity of cable is with the addition of new features: 40 ch;?,nnels, subicriber service for the time being will probahly Electronic importation of distant television sta- be `iunited to 35 channels. tions 12

Live studio programming exclusively for the munications Commission now reouires that all cable system systems with more than 3,500 subscribers must Automated programming of news and weather operate to a significant extent as a local outlet Multiple headend interconnection for large by origination cablecasting.' systems. Studio facilities for cablecasting vary in cost, 2. Distribution systems are beginning to have ranging from as low as several thousand dollars more capacity as many as 35 channels delivered for facilities bUilt around a half-inch black and to subscribers. white video tape recorder, to a full color profes- 3. Subscriber terminals will include devices that sional studio that may cost S1 million or more. bypass weakne,ses of the teleion receiver. Automated Programming HEADEND Many system headends now include automated origination providing specialized services other As in the traditional cable system, the headend than conventional telecasts. Automated equip- in a modern system includes the antennae, and ment packages provide time, weather, stock ticker the electronic control center for amplifying broad- and news (AP or UP) wire services, many with cast signals received and converting UHF signals alphanumeric message capability. At least one to VHF frequencies before transmitting them manufacturer markets a computer controlled vid- through the distribution system. Additional eocassette player, which permits the system facilities are now required to produce the new operator to play pre-recorded three fourth inch services. videotapes automatically.

Electronic Importation of Multiple Headend Interconnection Distant Television Signals Headends are now becoming increasingly complex because of the need for interconnection of. Cable systems are required to carry certain tele- systems. Interconnection is necessary when a vision stations which place a signal over the sys- communit-, st: large that it must be served by tem's service area. Cable operators offer addi- several headends and distribution systems (called tional program services by importing television "hubs"): It may also develop when several con- signals from distant markets. Since the signals are tiguouscable systemsinneighboring com- received near the distant market and transported munities interconnect to share local program- to the local headend by microwave radio systems, ming. one additional feature of a modern headend is Interconnection can be achieved by cable (in- the equipment necessary to receive and modulate cluding a new one inch cable with low signal loss microwave signals. characteristics, called "supertrunk"), or by mic- Microwave transmission is a system of broad- rowave. This microwave is not the one-point- casting from one point to another 20 to 35 miles to-another kind used to import distant television distant. To import a television station, a transmit- signals, but a new service called Local Distribution ter near the station radiates the signal in a specific Service (LDS). These microwave systems have the direction toward the distant receiver rather capability of transporting a large number of televi- than uniformly in all directions as is done with sion pictures (from 8 to 38) from one site to a radio and television broadcasting. Microwave sta- number of receiving locations, without visible tions must be cascaded when stations from great deu.Idation of signals (see Figure 7). Supertrunk distances are imported. For example, importing is usually favored over LDS where weather condi- a television station from a market 200 miles away tions do not allow reliable LDS operation or where might require "hops" between three to five mic- two-way capability is required, such as in a system rowave stations. Microwave service may be pro- with a number of local origination studios that vided by the telephone company, or by need to be interconnected. However, in urban specialized common carriers, or it may be owned by the cable system operator himself. 'In United States v. Midwest Video Corp., 406 U.S. 649 (1972), the Supreme Court upheld the FCC's authority to impose the origination requirement. In the course of that litigation, however, the commission stayed the effect of the rule. Upon affir- Live Studio Programming mation by the Supreme Court, the commission did not move to vacate the stay. There is some question, though, whether System operators frequently operate !ocal such action was necessary and the commission has not stated studios to program a channel. The Federal Com- whether the rule is in effect. 13

environments where underground construction is necessary, microwave may be the least expensive one-way interconnection system. In some circumstances, a combination microwave and cable system for two-way interconnection may be less expensive than an all-cable system. If interconnection of cable systems is desired (either presently or in the future), the technical standards for the distrih, n system must be more strict than those for .ind alone" system. Whether microwave or caith., is used to interconnect hubs, some additional distortions both more noise (snow) and more in termodulation arid cross-modulation (moving bars) will occur. As a result, to obtain the same quality signals as those carried by a single hub system, the number of trunk and feeder amplifiers cascaded in a multiple Figure 7. Microwave Interconnection of C.:ble Television Sys- hub system must be smaller. tems. Traditional systems use a one-way "tree" layout that can be likened to a party line that is, all subscribers share the same facilities and receive the same programming (see Figure 8). A "fully switched" system such as the nationwide telephone network permits two-way private line communications by connecting each subscriber directly to a vast network of switching centers and alternate signal routes (see Figure 9). Intercon- nection, if properly designed, helps offset the party line character of cable system. Interconnection permits headends to act as switching centers. Interconnection switching facilities allow one hub to receive programs of particular interest to its subscribers, while another hub does not. Or, switching facilities within a hub may also permit subscribers connected to a specifi, trunk to receive special programming (for example, a locally cablecast high school baseball Figure 8. Cable Television Systems Use a Tree-Shaped Network. game) while other trunks do not. Such limited switching capabilities are not nearly as sophisticated as the fully switched telephone system, but they do increase the flexibility of downstream one-way service and in the future may increase the efficiency of two-way services. Although switched cable systems exist, they are riot widespread in the United States. Switching centers are costly, and urban communities would require a large number of centers. Furthermore, the cost of laying the large number of cables required might be prohibitive, especially if the cables were placed underground.

DISTRIBUTION SYSTEM f", The modern distribution system consists of the same elements as the traditional one coaxial cable, amplifiers, and so on. However, with the Figure 9. Telephone Systems Use a Switched Network. 14 increase in the number of services provided, C. Broadband Communications several problems arise. As mentioned earkr, a standard television receiver is capable of receiving Cable's Future only 12 of the35 channels cable can carry. Further, Modern cable television has evolved from a a strong local broadcast signal will interfere with retransmission system providing basic reception a cable signal carried on the same channel when to an expanded medium for delivering one-way the two signals meet in the television receiver, services to subscribers. With the addition of making that channel unusable. Thus, distribution imported signals, au tomated origination, and local systems have to be modified to overcome these programming, cable television has surpassed the limitations. capabilities of broadcast television and is well on Two approaches have been developed to solve the way to becoming the "television of abun- these problems. The first, and generally the most dance" envisioned by the Sloan Commission.' expensive, is to bring additional cables to each Cable technology promises two-way communi- home and provide a switch allowing the subscriber cations for subscribers, and the potential of broad- to switch from cable to cable, receiving up to 12 band communication networks in the future. channels on each one. This approach uses only 12 of the 35 channels in each distribution cable but it does provide a means of receiving more THE EVOLUTION OF than the 12 channels on the television set. Further, CABLE TECHNOLOGY: this approach led the cable industry to develop TWO-WAY COMMUNICATION prototype advanced two-way systems based on the presumption of a dual cable distribution Cable's most glamorous aspectisits"bi- system. directional," or two-way, capability. For the most The second approach does not involve the dis- part, this capability exists now only in prototype. tribution system, but rather the subscriber ter- Little is known about the future market for two- minal. way communications; system operatoi ,, therefore, are likely to be cautious when considering SUBSCRIBER TERMINAL investment in two-way equipment. Two fundamental kinds of two-way systems are More recently, system operators have increased envisioned for cable communications: institu- capacity by installing a converter instead of extra tional two-way systems for a few users, and sub- cables. Depending on the model, the converter scriber systems for all subscribers. Institutional permits the subscriber to tune any of 26 to 35 two-way systems may involve two-way data com- cable channels. The converter translates the munications or two-way video communications. incoming signal selected by the subscriber to a Most of the electronics for these systems are VHF frequency the best suited to reception by already on the market. the television set. Thus, with a converter, a sub- Subscriber systems involve three prospective scriber may receive from 26 to 35 channels from levels of capability. a single cable. Greater channel capacity can be Subscriber response systems - very limited, party achieved by using both multiple cable and conver- line digital communications between subscriber ters. The converter rests on top of the television terminals and a computer at the headend, permitting such services as opinion polling. These sys- receiver and takes the place of the receiver's tuning mechanism (see Figure 10). Current versions tems exist in prototype and should soon be market tested by several multiple system operators cost about $23 to $35 each. (MSO's). They may be available commercially in two to three years. Subscriber initiated systems - expanded digital communications between advanced terminals and the headend. This approach may permit computer assisted instruction, remote facsimile reproduction, or other services. An experimental system of this type has been constructed in Reston, Vir-

'On the Cable: The Television of Abundance, Report of the Sloan Commission on Cable Communications, Edward S. Figure 10. A Switched Converter. Mason, chairman (New York: McGraw-Hill Book Co., 1971). 15 ginia. They are likely to be available commercially to one amplifier, and the other frequencies to the in less than six years. other amplifier. Switched video communicationsexists commer- Depending upon planned uses, the filters may cially; the telephone company offers limited permit either a roughly equal number of upstream switched video communications (video telephone and downstream channels (a "midband split"), or service) in Chicago. Two-way video telephone ser- the majority of the channels about 35 down- vice is not suitable for cable television systems, stream with a few three or four upstream because cable distribution systems do not have (a "subband split"). Figure 11 illustrates the dif- sufficient switching facilities, and cable systems ferences in spectrum use. are not widely interconnected. The choice between these two methods of con- In the next few years, only subscriber response trolling electronic traffic in the cable depends and closed circuit services are likely to be offered upon planned use. Midband split arrangements on cable systems. Later, subscriber initiated ser- are intended for closed circuit uses; there are a vices may be available. The technical description large number of upstream channels. The subband that follows deals with each of these kinds of ser- split arrangement permits 35 channels down- vices. stream and only four upstream; it is designed for subscriber response systems. Headend Subscriber Terminals For subscriber response systems, the major additions to the headend will consist of a compu- Advanced systems depend heavily upon the use ter to control communications with subscribers, of sophisticated home terminals that will include, and many more interconnection facilities besides the television receiver, such equipment perhaps including links with satellites to con- as facsimile printers, computer keyboards, and nect the local cable system with (projected) videotape recorders. Most subscriber services are national video and data networks. The computer predicated on a system of limited subscriber will send short, individually addressed electronic return communication called a "subscriber messages to each of thousands of subscriber ter- response" system. A small push-button terminal minals. Each terminal will respond with short data in the home (similar to a touch-tone telephone messages back to the computer at the headend. keyboard) receives periodic data messages from The responses would indicate the status of the the headend computer. A separate message is terminal, which might include the channel being addressed to each subscriber terminal. The ter- Watched, subscriber requests for information, minal, as shown in Figure 12, responds with a short subscriber responses to questions posed by a tele- data message upstream to the computer, which vision snow, or the status of a remote monitoring interprets and stores the messages from each sub- device such as a water meter or fire alarm. The scriber. Since the messages are short, many exchange of messages between headend compu- thousands of them can be sent in sequence over ter and terminals will take place in split seconds. the cable. Current versions of this system, now being tested, involve a computer which can inter- Distribution System rogate as many as 30,000 subscriber terminals in 22 seconds. The electronics for two-way transmission are Subscriber response systems, though limited to quite straightforward, if two cables are used. digital communications between the headend Amplifiers in one cable boost signals in the for- computer and subscribers, will permit several ward direction (headend to subscriber); amplifiers unusual kinds of services: in the other cable boost signals in the return direc- Opinion polling. Subscribers indicate their opin- tion ion regarding an issue posed on a cablecast Two-way signal transmission in the same cable program. The results are tabulated by the compu- is more complex. A housing which contains a cable ter and presented to those televising the program. amplifier is enlarged to permit these additional components: Home shopping by cable. Retail shops lease a A second amplifier, to strengthen signals being channel and display goods to subscribers, who sent upstream may make orders by keying ordering instructions A pair of electronic filters, which separate the into their terminals. The goods are later delivered signal traffic by routing one set of frequencies and the customers billed by the cable system. 16

MIDBAND SPLIT

Upstream Crossover Downstreamwillamm4111 signals filters signals

16 Return 23 Channels Channels

5 30 54 88 108 160 174 216 MHz 300

SUBBAND SPLIT

Upstream Crossover Downstream signals*"signals*" filters ...4.. signals 4 5 9 7 14 Return Low VHF FM Mid-Band High VHF Super-Band Channels Channels Channels Channels Channels Channels (2-6) (7-13)

5 30 54 88 108 174 216 MHz 300

Figure 11. Difference in Spectrum Use

Pay television. Some channels will be scrambled, system. On this level of service, communication unless unscrambled by a command from the between subscriber terminals and headend com- headend computer. A subscriber may view first puter is greatly expanded, though still digital. The run movies or other special programs, paying a subscriber may initiate communications by send- fee-per-program, by indicating to the computer ing data messages to the computer, rather than through the home terminal to unscramble the pay waiting to respond to computer electronic inter- tele% ision channel. The subso:ber is billed at the rogation. This gives rise to potential uses such end of the month.' as computer assisted instruction, random access Remote sensing. The headend co -nputer records to library materials (assuming they have been con- signals sent via the home terminal from fire and verted to digital form), ticket reservations, direc- burglar alarms, or automatic reading of utility tory services, and catalog shopping. In addition meters. to the television receiver, subscriber initiation ter- At a considerably higher level of technical minals might include several other devices, such sophistication and cost than the subscriber as a remote printer, a video tape recorder, and response system is the "subscriber initiated" a full alphanumeric keyboard. One conceotion of such a terminal is shown inigure 13. Implementation of all 'wo-way services is still at the experimental level. The necessary technology is reasonably well developed, but the market for services is not known and the costs connected with providing them are hard to estimate. Cable hardware costs are easily determined; but nearly all two-way applications require the use of computers. The cost of programming these and the computer associated software may be a critical factor in the economic feasibility of two-way applications. Another important element

'Pay TV can be provided without subscriber response capability in the cable system. Several different systems which do not Figure 12. A Subscriber Response Terminal. require two-way capability are being market tested. 17

is the cost of terminal equipment in the sub- Two-way vioeo. As an example, a video link scriber's home. One-way cable requires only a between a doctor and a paraprofessional who is television set and perhaps a convener. Present located at a remote medlual clinic could be used estimates of the cost of terminal equipment for to improve health care in aural areas. each home indicate that subscriber two-way ser- Data interconnection. A computer in one depart- vices will be very expensive. However, technologi- ment of a city could be interconnected to another cal advances and mass production techniques may department's computer. Banks and branches, hos- reduce terminal costs to economically feasible pitals and clinics, downtown retail stores and sub- levelsas they did in the production of television urban branches each have data interconnection receivers and subscribers may well be willing needs. to pay more if they feel the services provided are worthwhile. Institutional Two-Way Systems FUTURE COMMUNICATION SYSTEMS AN THE CONVERGENCE Subscriber services are limited because of the OF TECHNOLOGIES large number of users. If, for example, all subscribers were equipped with conventional video How well two-way approaches meet the test.of cameras as part of a video telephone system, 20 the market depends not only upon cable television two-way video conversations would exhaust the technology, but also upon the parallel develop- capacity of a single cable. ment of competing technologies. Cable television However, if there are few users, a full range is neither the only new develop,:ient in modern of communications services, including two-way telecommunications, nor the answer to all com- video and high speed data, can be offered. Appli- munications needs. Itis worthwhile here to cations of this kind are called institutional uses examine what things cable cannot do, and to note because they are normally operated outside the developments in competing technologies as well. general home subscriber network, as for example, in businesses, schools, hospitals, or public Capacity Limits agencies. But, if an institutional function does not use many channels, it may be provided on some Theoretically, there are no real limits to cable of the unused frequencies of the main distribution capacity: new capabilities can be purchased in system. Uses which require a large number of blocks of 40 channels simply by adding more channels are best provided with a private cable cables. In practice, however, cable is limited to connecting the few users. the capacity that can be provided competitively Some of the projected services for closed circuit when the costs of other modes of telecommunica- uses are: tions are considered. Systems equipped with subband split subscriber two-way electronics (see page 13) are not suitable for widespread use of two-way video. Typically, 2,000 or more subscribers would share the three to four return video channels on a single feeder equipped with subband split amplifiers (35 channels downstream, three tc four channels upstream). Even closed circuit cable with midband split amplifiers permits only 16 channels of upstream video signals. One frequently mentioned use of cable technology would permit an individual subscriber to request a specific videotape from a library of tapes. This application must be viewed in terms of the number of potential downstream channels. While current systems may have reserve capacities of 20 to 30 channels per cable, the sharing of these downstream channels by thousands of subscribers Figure 13. One Conception of a Subscriber Initiation System could quickly exhaust the resources and create Terminal. a shortage of channels. Clearly, a typical cable 18 system could not expect to respond to the request New transmission mediums for the simultaneous viewing of more than a few tapes, certainly not hundreds, before all the avail- A frequently suggested "cure" tor more capacity able downstream capacity was exhausted. is new transmission mediums. Two that have been It the demand for these types of services frequently mentioned are wave guides and fiber becomes high, additional capacity could be optics. Both hold promise of huge channel installed. But, for the near future, cable systems capacities. may not be installed with such additional capacity. Wave guides are carefully fabricated hollow Further, there are limits to the number of cables metal tubes which efficiently carry Super High that telephone poles and underground ducts can Frequency radio waves. Potentially, wave guides carry. may carry from 400 to 800 television channels of One means to increased capacity, where con- capacity. tinuous motion video is not required, is in the Fiber optics involve transmission of light use of "frame-stoppers," which permit timeshar- through very thin glass fibers. The light signals ing of a video channel. A television picture are coded to carry television signals or data infor- just as a motion picture consists of a series mation which are carried by the light beam as of still pictures or "frames." Every one-thirtieth it travels th rough the fiber. The bandwidth capac- of a second a new frame is transmitted elec- ity of optical fibers is breathtaking as many as tronically. Each frame is a complete picture.If 2,000 television channels or more. there is no movement in a TV picture then each Both systems are in the develcpment stage. Cur- frame transmitted is the same as the previous rent work on wave guides is several years from frame. fruition and is designed to provide long distance A frame-stopper terminal receives a frame, dis- telephone transmission. Several characteristics of plays it on a TV screen as a normalTV set does, the current work make it totally unsuited for local and stores it electronically. Then instead of receiv- distribution of TV signals. The use of fiber optics ing the next frame transmitted as an ordinary TV for transmission is evolving rapidly, but develop- set does, the frame-stopper ignores the new frame ment of devices to connect the fiber lines to and replays the stored frame for a specified headend or terminal facilities is lagging. Develop- period. It is possible to electronically "address" ment of a broadband communications system with a frame as it is being transmitted. A frame-stopper fiber optic transmission may be 5 to 10 years away. terminal can then look at the address on each Itis possible that coaxial cable will become frame and receive only those frames addressed obsolete, but the role of cable television as a to it. broadband local distribution communications sys- Thus, if all subscribers are equipped with frame- tem will remain for the foreseeable 'future. stoppers programmed to replay a stored frame for 10 seconds, 300 subscribers can view still pic- Prospects for Switched tur,r) addressed individually, using only one tele- Video Communications n channel. This mode of "slow speed television" would be use;ul for such applications as Cable television communication witha tree computer-assisted instruction, remote catalog shaped distribution system is an awkward base shopping, or listing poison antidotes. for the development of a fully switched network Frame-stopping technology is still in a state of that will allow one subscriber to dial another, as flux and no commercial firm has yet mass pro- with the existing telephone network. It does not duced a low cost frame-stopper, (under $100 per use local exchanges which permit flexible and reli- terminal), although $500 to $700 per terminal now able connection between random subscribers, appears to be a feasible cost. except through the headend. A cable television Most future subscriber applications discussed system may never be convertible to a switched in the general literature, like frame-stopping broadband network, without costly rebuilding. technology, require the use of sophisticated home Further, the cost of a completely switched video terminals. To date, no inexpensive units have been telephone system service nationwide would be developed. As currently projected, home termi- extremely expensive. One estimate is $12,000 per nals would range in cost from $90 to $300 less subscriber (as compared to $600 per subscriber converter (converter costs are $30 per subscriber). for the existing telephone network). Any decision Widespread implementation of two-way cable ser- to build complete video switching between all vices is dependent upon the development of subscribers would involve a national policy com- highly reliable, low cost terminals. mitment of at least the magnitude of the Interstate 19

Highway System. The switching capability that is II. MAJOR ISSUES currently feasible is based upon very limited access because of the small number of upstream FOR FRANCHISING AUTHORITIES (subscriber to headend) video channels. A few manufacturers have produced hardware that Understand;ng cable technology is important to would provide for limited switching but the pro- local officials because they are faced with technical decisions about cable televisionin their com- jected costs have been two to eight times the cost munity. This part of the report examines three of unswitched cable systems and so have not been kinds of technical questions local officials must popular with cable operators. deal with. Other Communications Media Design decisions must be made before any operator is franchised, and are nearly irreversible Other telecommunications media offer some of once the system has been constructed. -the same services envisioned for cable television, Performance issues must be decided before notably pay television and data transmission. The franchising, but they also present a continuing first pay television services were offered commer- responsibility to the franchising authority for cially via Multiple Distribution Service (MDS) mic- ensuring that performance standards are met. rowave. MDS broadcasts television signals to spe- State of the art issues cannot be resolved since cial receiver systems of the type that could they will be future problems. However, local offi- economically serve a number of TV sets at a single cials must decide what mechanism they will create location such as motels, hotels, and apartment in the franchise to ensure that the franChising buildings. authority has a role in keeping the system The telephone system already provides data technologically up-to-date. transmission service. In addition, the telephone industry is building an all digital network which A. Design Decisions will eventually lower the costs of data transmission. Other companies have-been created to serve Some design decisions are of such importance as specialized common carriers and will provide to the community that they should not be left a digital network for computer communications. entirely in the hands of the system operator. Local In such systems, however, cable may still serve officials ought to take a large share of the responsi- as the local distribution system between the car- bility for making decisions on at least these six der and the subscriber. questions: 1. What kinds of facilities should be constructed SUMMARY for public use of the system? 2. How much present and future capacity should Cable television has evolved from a retransmis- be built into the cable system? sion medium as traditional CATV, to modern cable 3. What kind of two-way facilities should be instal- television an important and exciting medium led at the outset? on its own merits. Most of cable television's 4, How should service areas be defined? technical magic lies in the future. But its present 5. What interconnection capacity is needed? capacity to deliver an expanded "menu" of one- 6. What can be done to extend service to less way video programming results from major dense areas? technological developments in the past 10 years. Local officials are not required by the FCC to In the near future, subscriber response and answer each of these questions, but failure to do dosed circuit two-way developments are likely to so leaves the decisions entirely in the hands of be developed and perfected, opening prospedts the system operator. Once made, the decisions fora vast new range of services. In the more distant are often practically irreverFioe because of the future, broadband communications may move high cost of cable system pint and installation. from coaxial cable to a new medium, such as optical glass fibers, or some yet undiscovered WHAT KINDS OF medium. But regardless of its mode of transmis- FACILITIES SHOULD BE sion, cable television as a local broadband dis- CONSTRUCTED FOR PUBLIC tribution system is likely to remain in existence USE OF THE SYSTEM? for the foreseeable future. Plans and decisions made now by franchising authoritie.; are unlikely The commission's rules require only that cable to be invalidated by rapid technological evolution. operators in the 100 largest television markets fur- 20 ni5h channel space for access cablecasting, and Test equipment maintain production ,iacilities within the franchise Studio lighting and equipment. area for use on the public access channel.' It should be emphasized that these studio pack- However, the system operator may also agree to ages represent a relatively at,stere investment in furnish equipment as a condition of the franchise comparison with broadcast studio facilities, which agreement and it is in the interest of the franchis- may run into $1 million or more. Further, these ing authority to develop specific priorities of figures represent only capital outlays. Operating facilities desired before a franchise is granted. expenses can easily total from $20,000 to several Further, the full public value of a cable system hundred thousand dollars a year. Planning for will not be realized without investment in public studio facilities, therefore, should include careful facilities, such as educational programming operating budgets as well as capital costs. studios, that will not be provided by the system operator. Local authorities interested in promot- Other Public Facilities ing the publicservices on cable television will havc to plan for thedevelopment of additional facilities, Many communities tend to think of public cable the manpower to use them, and the money to services in terms of the three access channels pay for them. defined by the FCC's rules. However, cable televi- For policy planning purposes, facilities for the sion systems offer exciting possibilities for closed cable systems fall into two general categories: circuit uses that may enhance the quality of in- Studios and equipment for public access and school education, health services delivery, and local origination other public services. Planning for such pos- Other public facilities. sibilities involves consideration of a broad range of terminal equipment. Listed below are some Studios and Equipment for illustrative examples. Public Access and School Facilities Local Origination Taps to each school The origination facilities provided by a system Taps to each classroom (far more expensive) Videotape recorders operator should be designed to meet the needs Studio facilities for local program production of the community served. The range of studio within the school options is so broad that facilities can be designed Closed circuit network connecting all schools only after the franchising authority has weighed Facilities to permit school studio programming its planned uses against capital costs. The costs to be distributed to all subscribers of live studio facilities, whether owned by the sys- Hospital Facilities tem operator or the community, vary enormously. Patient room taps The following figures illustrate some possibilities. Operating room studio equipment Low Cost Black and White Studio - $25,000 Closed circuit interconnection of hospitals and Two live black and white cameras clinics One 16mm film chain Three 1/2" black and white portable video Library Facilities tape recorders and cameras Videotape recorders and tapes Moderate Cost Black and White Studio - $50,000 Camera equipment. Three black and white studio cameras Film projector HOW MUCH PRESENT AND Slide projector Studio lighting and equipment FUTURE CAPACITY SHOULD BE Special effects generator BUILT INTO THE CABLE SYSTEM? Two 3/4" video tape recorders Two 1/2" portable recorders and cameras Most discussions about cable system capacity Moderate Cost Color Studio $150,000 center on channel capacity of the distribution Three color studio cameras system. But distribution capacity questions are dif- Special effectS generator ficult to resolve without an estimate of local prog- Control room electronics ramming demands on thesystem. For example, Film and slide projectors a ten channel local education network, in conjunc- Two color video tape recorders tion with TV signal carriage, would nearly saturate Three black and white video tape recorders a 35 channel system. Decisions about present and 'Cable Television Report and Order, 47 C.F.R. 76.251(a)(4), future channel capacity should be made in con- (1972). junction with estimates about the development 21 of various sources of local users. Unfortunately, examined in terms of capacity now and in the it is very difficult to develop meaningful estimates future and cost implications. The special case about corqmunications uses that presently exist of low cost service to less dense areas is evaluated only on a very small scale. FCC requirements for later in another section. educational, government, and public access chan- Within present cable industry practice, there are nels providi? little guidance for the development five primary methods of sending signals from the of future programming. headend to the individual subscriber; four of Further, system operators tend to view imported these methods comply with FCC requirements for signals as more attractive offerings to subscribers, the top 100 television markets, and the fifthis than local programming. Thus, the development suitable for cable television systems outside the of local programming will depend on the quality major markets. Since all cable systems consist of of local planning and interest. trunk cable and feeder cable, the major distinc- There is no proven method for accurately tions between these alternatives involve the assessing the elements of any community which number of each type of cable required to provide will make use of local programming. Not many customer service. The alternatives are: examples of productive uses exist, and few local 1. Single Trunk Single Feeder (see Figure 14). institutions are in a position to plan precisely how they will use such an unknown resource. Local A single electronically active trunk cable is laid from the hub to the neighborhood; a single active officials are faced with very difficult choices about capacity demands, and the elements of the feeder cable is then laid past each home; a single drop cable enters each home and is connected choices are not clearly defined. Local officials can, however, consider the cost to the subscriber's television set. "Active" cable is installed with the necessary of system capacity, and weigh it against an assess- electronics to carry electronic signals in one or ment of the number of users in the community both directions. The electronics, depending upon who will make use of local programming. Any the cable's purpose, include amplifiers to boost assessment is bound to be uncertain and signal strength, splitters to divide the signal at the speculative, since few potential users will be able cable junction, taps to draw the signal into the to predict accurately what demands they will make subscriber's home, etc. on the system. Nonetheless, an informal canvass The capacity of this system is restricted by the of public school or university activities and capacity of the television receiver 12 channels. resources, for example may give local officials This system does not satisfy FCC requirements a sense of some of the demands that will be placed for systems in the 100 largest television markets, on system capacity. Decisions about capacity may although it might be appropriate for smaller sys- tiien be more informed. tems outside the top 100 markets. Local officials should also consider the cost of system capacity, since costs ultimately will be 2. Single Trunk - Single Feeder - reflected in both subscriber rates and the Converter (see Figure 15). economic viability of the system. In the discussion A single active trunk cable is laid from the hub that follows, distribution alternatives are to the neighborhood; a single active feeder cable

Figure 14. A Single Trunk Single Feeder System without a Figure 15. A Single Trunk Single Feeder System with a Converter. Converter. 22

is then laid past each home; a single drop line Installation of two-way electronics again permits enters each home; and a home converter is four channels from subscribers to the headend. attached to each subscriber's TV set. With the installation of midband split, two-way The capacity of such a system standard coaxial electronics, the second trunk cable may be used cable with available converters is approximately for closed circuit uses. This arrangement provides 26 to 35 channels. Installation of two-way elec- point-to-point communications up to 23 channels tronics permits four channels to be carried from downstream and 16 channels upstream s. -ribers back to the headend. Current design 4. Dual Active Trunk J aches within the industry are probably Dual Active Feeder - re6,..dng a consensus that this option is a relatively A/8 Switch (see Figure 17). inflexible alternative, not permitting economical This distribution system includes two active future expansion. trunk cables, two active feeder cables, and a However, there is a legitimate argument for this switch at the home TV set enabling the subscriber alternative. If u'ile services develop slowly, then to switch from cable A to cable B. In order to it will be less expensive to install one cable and select one of 12 channels on each cable, the chan- wait to install another cable until uses are gener- nel selector on the set is used. ated. In other words, this argument asserts that The theoretical maximum channel capacity of because of the time-value of money despite this alternative is 24 channels. The actual max- inflation and higher installation costs the dollars imum is often less since a strong off-the-air signal invested in the future might be less than the cost causes interference to the signal carried on the of installation of the second cable presently. same channel in each cable. With three or more If local officials should prefer a single cable strong local VHF stations, the maximum number system, the principal financial impact of such a of channels that can be obtained with dual cable choice would be is less than 20. Thus, this alternative has, in the lower capital costs; and short term, relatively low channel capacity. Expan- the probability that the system would earn an sion to high capacity in the future is relatively easy, acceptable return on investment. with the addition of a converter (provided the sys- 3. Dual Activellnactive Trunk tem is initially constructed with electronics cap- Single Feeder able of carrying 35 channels of signal bandwidth). Home Converters (see Figure 16). Except in very densely populated areas, this alter- This distribution syStein includes two trunk cab- native involves higher capital costs per user than les; however, only one of the two contains the the other alternatives. electronics necessary for signal transmission. The other, a "shadow" cable, contains no electronics. 5. Dual Activellnactive Trunk The system includes a single active feeder cable, Dual Active/Inactive' Feeder and a home converter which substitutes for the Home Converter (see Figure 18). television set's channel selector. This system is This distribution system, like the previous alter- capable of delivering 26 to 35 channels to the home native, includes two trunk cables and two feeder at the time of installation. cables. However, only one trunk and one feeder cable are active; the other trunk and feeder cables are inactive. The system includes a converter and is thus capable of delivering 26 to 35 channels to the 'dome immediately. Expansion to 70 channels per subscriber is made possible by the addition of electronics to the second cable.

'A number of the issues involved here are matters of contention within the cable industry. Particularly controversial are the general choices between #3 and #4 above. Choice #3 requires .14 a high number of subscribers per mile to be immediately com- parable in costs. On the other hand, choice #3 is easily expan- dable. Choice #4 involves the use of converters which are undergoing rapid technical evolution and whose maintenance costs are in doubt and expansion requires adding electronics. Yet, choice #4 yields more immediate capacity. The most accurate general statement that can be made is that an appropriate choice depends in part upon the particular community, in part Upon the development of converters and cable Figure16. A Dual Trunk Single Feeder System witha electronics, and in part upon the speed with which new uses Converter. require the expansion of cable capacity. 23

Figure 17. A Dual Trunk Dual Feeder System with an A/B Figure18. A Dual Trunk DualFeeder System with a Switch. Converter. The distribution alternatives are summarized in tions about the development of future services Table 2. An important aspect of each of these dis- and capacity needs. tribution alternatives is a basic fact of construction Depending upon geographical layout and den- economics: although cable and electronics cost sity, a cable system will require from two to five the same regardless of when installed (discounting times as much feeder cable as trunk. Thus, the inflation), installing a second cable along with the installation of a second feeder cable is expensive first is far cheaper than installing it later. no matter when itis undertaken. If a shadow Alternatives #3 and #5 make use of these con- feeder cable is installed at the outset, distribution struction economics. Each has dual trunk cables; costs, including cable, increase about 20 to 40 per in addition, alternative #4 has dual feeder cables. cent. But if the second feeder is installed at a later A dual trunk-single feeder system includes date, it will cost at least twice as much as the shadow trunk and shadow feeder cables. There first feeder. is a substantial difference between the two alterna- This dues not imply that activating the second tives in terms of capital costs as well as expecta- cable will be easy or inexpensive. Conversion of Table 2. Distribution System Alternatives

Alternative Capacity Expansion without Rebuild

1. Single Trunk-Single 24 channels or less to 35 channels to subscribers; Feeder subscribers 4 channels subscriber return

2. Single Trunk-Single 35 channels to 4 channels subscriber return Feeder - w/Converter subscribers

3. Dual Trunk-Single 35 channels to subscribers; 35 channels to subscribers; Feeder - w/Converter some institutional two-way 4 channels subscriber return; institutional two-way

4. Dual Trunk- 24 channels or less to 35-70 channels to subscribers; Dual Feeder subscribers 4 channels subscriber return; institutional two-way

5. Dual Trunk-Dual 35 channels to subscribers; 70 channels to subscribers; Feeder-w/Converter some institutional two-way 4 channels subscriber return; or institutional two-way 24

shadow to active trunk involves not only the instal- HOW MUCH TWO-WAY lation of, both forward and reverse trunk CAPACITY SHOULD BE amplifiers, filters, and accessories, but also the INSTALLED AT THE OUTSET? connection of feeders from cable A to trunk cable B and adjusting cable Li electronics for two-way. Subscriber two-way systems are still in the pro- The second feeder decision involves more than totype stage, and, for the time being, few com- financial outlays. A dual trunk-single feeder sys- munities will enjoy subscriber response service. tem can accommodate subscriber response -two- There are, however, several other ways that two- way technology without a second feeder. The way cable communications can be employed pre- main "downstream" trunk is retained for one-way sently. They can be conveniently grouped in three delivery of 35 channels to subscribers. When elec- categories: tronics are installed in the second trunk, and it Two-way systems for origination at locations is connected to the feeder, subscriber response away from the headend traffic can be carried back to a computer installed Two-way closed circuit systems at the headend. The second trunk is two-way, and Community information and service center thus can also be used for two-way, point-to-point systems. (closed circuit) uses. The use of the second trunk cable for closed Origination Away from the Headend circuit applications is limited by the fact that trunk passes only about one-quarter of the homes and There are two means by which programs can buildings in a city; the remainder are reached with be originated away from a. main studio: mobile feeder cables. Unless a prospective closed-circuit vans, and remote studio facilities. user is located near a trunk, he cannot use the A mobile van permits origination virtually any- service. The cable industry, for the time being, where, but programs cannot be carried live with- solves this problem by extending the second trunk out a microwave hookup to the headend. to areas where closed circuit users are located, Similarly, a permanent studio cannot originate live or by installing a special feeder. programs if itis not connected electronically to But; in general, it is difficult to predict prospec- the headend. tive dosed circuit users and the kinds of services The franchising authority must decide whether that wiil be required. If the decision is left to the live programming uses planned for origination system operator, extra trunk or a second feeder facilities justify the costs of interconnection with cable may be installed only to those places where the headend for live programming. Even if there closed circuit users have been clearly identified. are no formal cablecasting facilities, origination That decision is properly one for the franchising from such places as high school basketball gym- authority, not the system operator. The great nasiums may warrant installation of the cable to expense of a second feeder, installed later, would permit live cablecasting. naturally make a system operator reluctant to undertake the investment, regardless of the city's Institutional Two-Way Systems needs.If the franchising authority anticipates great educational or local government demands Two-way services such as data interconnection for closed circuit uses (or more than 35 channels and video teleconferencing are feasible on cable, of subscriber services), it may wish to require the providing the number of users is limited. Institu- immediate investment in a second shadow feeder. tional uses can be provided on unused channels To summarize these arguments: on the main system of cables, or by designating Single trunk and feeder systems, although particular cable for institutional users. For example, each of 40 schools or libraries might be limited in expansion capacity, are less expensive options and do not require investment in cable assigned a channel on a cable interconnecting all of them. With studio facilities at each school, any that might not be used. school could transmit to all the others. Or, alter- Converters are more economical for systems natively, as many as 20 video conferences between with few subscribers per mile; A-B switches are two schools (for debates, for example) could take a better initial step for systems in densely place simultaneously. populated areas. Hospitals and local clinics might be intercon- The decision to invest in a second feeder nected to permit remote diagnosis (video signals depends upon judgment as to which kind of two- from the clinic to the hospital), orto permit remote way services will develop most rapidly: closed cir- observation of complex surgery (video signals cuit uses, or subscriber services. from the hospital to clinics). 25

Community Information and Service Centers terminals could be located in each center initially, with the ability to increase the number as demand Three prOblems have become apparent to many warranted. A one-way only receiving point would of those concerned about cable's possible public require merely a television-set preferably color benefits. and a converter; a two-way terminal :would, Not everyone will subscribe to the system in addition, have an electronic keyboard, Two-way services which seem to have great headphones, and auxiliary electronic equipment. public possibilities will be activated on a large Audio and video cassette machines could be scale only upon evidence that they can make situated on carts and checked out when needed. money Implementation of two-way s.-Irvice requires expensive terminal equipment in the homes of subscribers. These problems, taken together, mean that the public benefits of cable television may not be available to those who need them most, and that the most interesting public uses those involving two-way cable may have to wait (or the development, of profitable commercial uses. In the meantime, local officials might consider the possibility of establishing public community information and service centers. Such centers could provide a central point to which citizens could bring questions and problems relating to a wide variety of governmental services, linking the public to local government and public service agencies via two-way communications systems. They would make cable TV free to those who could not afford it, ensuring that 100 per cent of the population could receive public services by cable television. They might allow the Figire 19. A Community Information Center Terminal. limited introduction of two-way services; and they might assist in making local government more The MITRE Corporation, which has done exten- responsive and comprehensive.' sive research on remote access to computers via The information and service centers would cable and on computer assisted instruction, has probably have their greatest value and most use estimated the cost of such a system: if they were located in multipurpose community Excluding system integration and installation facilities. A neighborhood center combining adult costs, but including the cost of the computer education, recreation, library services,. meeting and all required hardware for audio, color rooms, social services counseling, and other and video tape capabilities, the pro-rated cost municipal services would be an optimum choice. amounts to $3,600 per terminal ... If a moder- Cable receiving facilities could be arranged for ate (25 systems) number of systems were constructed in mass in 1975, the total cost of the individual and group viewing (see Figure 19). And system willfall to $2,000 per terminal and two-way terminals could be situated in carrels probably further.2 affording user privacy but allowing for easy access to assistance when needed. A small number of These figures do not include software development costs which usually represent the "hidden 'See Alan R. Siegel and Calvin W. Hiibner. Special Services part of the iceberg" in programs of this kind. to Neighborhood and Home: A Community Telecommunica- Activation of two-way capability on a wide scale tion Demonstration Concept, Paper for the international represents a substantial investment in system elec- Telemetering Conference, October 10, 1972. Siegel, director, tronics and home terminals, It is not likely to be and Hiibner, program analyst, Community Environment and Utilities Technology Division, Office of the Secretary for undertaken except on the expectation of adequate Research, and Technology, U.S. Department of Housing and return. At the present time, there is no convincing Urban Development, state in a footnote that neighborhood evidence to support such an expectation. facilities under specified circumstances are eligible for federal support for up to three-quarters of facility construction. See 'Toward a Market Success for CA! An Overview of the TICCIT Title VII, Housing and Urban Development Act of 1%5, 42 Program (McLean, Virginia: MITRE Corporation, June, 1972). U.S.C. 3101. An excellent discussion of computer assisted instruction. 26

An intermediate step that might be considered would be to first implement two-way service only HEAD END to community information and service centers. 7 MILES This would both lessen the investment in hard- TRUNK - ware and share the benefit of that investment among a large number of users. Information centers could then test the feasibility and public acceptance not only of social services on cable but of many commercial services as well.

HOW SHOULD SERVICE AREAS BE DEFINED? FEEDERS

The actual layout of the cable distribution system is an important issue for the entire com- Figure 20. Subdistricts Defined by the Cable Television Distri- munity: the layout design will arbitrarily bring bution Layout. together or segment existing neighborhoods and communities of interest unless careful planning districts be defined. Districting carries with it the is performed in advance. possibility that undesirable community bound- This character of the cable distribution layout aries (such as railroad tracks which have separated will be reinforced if different parts of the cable communities racially or by socioeconomic status) will become reinforced. If the franchising author- system can, as the need arises, receive separate programming. This would be the case if the system ity elects to define trunk subdistricts, it should were made up of several interconnected hubs. then consider locating origination facilities within However, when a single system is equipped with the subdistrict, to permit local programming for relatively inexpensive switching equipment at the residents within that community to flourish. headend, it is possible to distribute programming If the cable system involves more than one to subscribers connected to one of the system's headend, the franchising authority must make ser- main trunks, without distributing it to subscribers vice area decisions. Fundamentally, there are two on the other trunks. The area served by each main kinds of decisions involved. trunk thus becomes a subdistrict, in which sub- Can (and should) the boundaries for a single scribers may receive programming transmitted hub be defined to coincide: with other political only to them. and social boundaries? This approach to localizing the programming Should the hubs be defined in terms that will provided by the cable system can be duplicated permit each hub service area to be franchised to by extravagant use of channel capacity. Local a different owner? programming for a neighborhood can be provided The question of boundaries is not one of simply by designating a channel for that com- technology, but rather of local community feelings munity. However, that approach rapidly exhausts and expectations about education and public system channel capacity. Districting arrangements access programming. The second question, that conserve channel capacity by allowing channels of multiple franchises, involves a different set of to be used over and over again in different parts issues mostly economic and organizational of the system. and implies a positive role for experimentation The boundaries of a trunk district are shaped and competition between types of ownership and principally by the technical limitations of cables management. The few communities large enoug;, and distribution electronics. In practice, these to face the prospect of a multiple hub system held limitations are not overly restrictive. The feeder opportunities for making the cable system socially network connected to a single trunk extends ser- more productive, if intelligently planned decisions vice about three-quarters of a mile on each side are made. of the trunk. Thus, a trunk district can be as large as 1.5 X 7-10 miles, or smaller, if desired (see Figure WHAT INTERCONNECTION 20). CAPACITY IS NEEDED? Within those constraints, boundaries can frequently be defined to coincide with neighborhood There are generally two interconnection situa- boundaries, school districts, or political jurisdictions. Each involves vastly different procedures tions. Of course, it is not mandatory that trunk for solving the problems to be encountered even 27 though the technical means may be identical. However, local interconnection isrelatively Interconnection issues arise under these two cir- new. There are several different kinds of intercon- cumstances: nection means, with different costs and Interconnection of hubs within a multihub sys- capabilities, and the regulatory framework for tem serving a single city. each is different. The discussion that follows con- Interconnection of systems serving several tains costs and capabilities of the basic possibilities adjacent communities (a development that is likely and a description of the FCC's regulatory require- to increase as communities share educational cab- ments. lecasting, etc.).' Interconnection of hubs in a multihub system Cable is a design issue that should be planned and decided upon before a franchise (or several Headends can be linked with cable to provide as many c..annels as needed, one-way or two-way. franchises) is issued. The planning process is com- plicated by the fact that each kind of microwave Each cable can provide up to 40 channels one-way interconnection mode imposes different FCC at a cost of about $2,800 per mile, or 20 channels licensing requirements. In some cases, the each way for two-way at a cost of about $3,300 franchising authority has no regulatory role per mile. The commission has not acted explicitly because the microwave service is fully regulated to define its role in cable interconnection of by the commission. headends. Interconnection of cable systems in separate political jurisdictions differs procedurally from Local Distribution Service Microwave (LDS) multihub interconnection within the same juris- With a single transmitter ($100,000) and multiple diction in two respects: receivers ($7,000 each), a system can distribute Interconnection is an issue that usually arises up to 18 channels one-way to many headends. after franchises in each community nave been Doubling the number of transmitters and granted. As a result, it is difficult to anticipate the receivers permits up to 38 channels one-way. LDS precise farm of interconnection requirements and could be used to provide 18 channels of two-way provide for them in each franchise. service between two headends, but it would nor- Interconnection of systems under different mally be more expensive than common carrier franchising jurisdictions creates problems for local microwave (see below). officials, both in terms of planning and in terms The FCC regulates LDS fully in accordance with of acting in concert. If no central authority exists Section 78 of its rules.It licenses the service to bring about agreement between system explicitly for the distribution of signals from one operators and each of the communities involved, or more receiving points, from which the com- planning for and developing interconnection may munications are distributed to the public by cable. turn out to be an extremely complex problem, one that is mainly political. For this reason, inter- Long Distance Microwave connection of communities for exchange of local and regional programming may be appropriate for Chains of receivers and transmitters provide state regulation. efficient point-to-point microwave interconnec- This paper does not address the procedural dif- tion one-way or two-way over great distances. A ferences between the two kinds of intercon- transmitter for one channel costs $10,000; the nection. Instead, it focuses on the specific techni- receiver $5,000. This kind of service is suitable cal alternatives available to interconnect systems for interconnecting a headend with a distant for different purposes. station, but it is less efficient for interconnection There already exists a great deal of interconnec- of several local headends serving contiguous dis- tion for long distance carriage of television signals. tricts. This service is provided by the telephone com- The FCC regulates common carrier microwave panies and by specialized common carriers, who service by licensing the carrier. otter the service to both broadcast television networks and to cable television systems. Instructional Television Fixed Service (ITFS) Microwave

'There is a third kind of interconnection for delivery of com- This low cost service is designed to interconnect mercial programming in effect, cable networks. These are not considered since franchising authorities have no jurisdic- schools and colleges, but is occasionally used for tion. other public services as well. A four channel trans- 28 mitter costs $36,000; each four channel receiver becomes more expensive. Local officials faced $500. It is clearly far less expensive than other with the problem of low population density (e.g., forms of microwave service. 20 homes per mile) must be concerned with The FCC fully regulates the provision of ITFS minimum service at lowest cost, rather than the through Part 74 of its rules: provision of excess capacity in the system for A license for an instructional television fixed future use. station will be issued only to an institutional Recent technical developments permit signifi- or governmental organization engaged in the cant opportunities to reduce the capital cost per formal education of enrolled students or to mile, and make the service available to more rural a nonprofit organization formed for the purpose of providing instructional television subscribers.' material to such institutional or governmental Modern broadband solid state line extender organizations, and which is otherwise qual- amplifiers are cheaper than older trunk amplifiers, ified under the statutory provisions of the and provide better performance. These line exten- Communications Act of 1934, as amended. ders are not as sophisticated as transistorized A nonprofit organization which would be trunk amplifiers, but for small communities they eligible for a license for a noncommercial will provide up to 35 channels of service and the educational television broadcast station is considered to be eligible for a license for an prospect of two-way subscriber response in the instructional television fixed station.' future, at a fraction of conventional costs. A smaller system can use smaller size cable and Planning for capacity, as for distribution system capacity, depends upon expectations about prog- low cost line extender amplifiers spaced to pro- ramming resources. If a multihub system is con- vide 35 channels of service. Further savings can structed to provide programming at each hub be achieved through the use of messenger cable headend, then interconnection of hubs should be coaxial cable which has the supporting steel two-way to allow programming to be distributed cable built into it. Table 3 below indicates the to the entire system from each hub. difference in cost per mile of installed aerial cable: If several communities interconnect to share facilities, such as a college television studio or Table 3. Cost Per Trunk Mile access programming facilities, interconnection (for transportation and distribution) needs may be met with a multipoint one-way interconnection system such as LDS or ITFS microwave. 3/4" cable using trunk & bridger amplifiers, typical Despite the regulatory jurisdiction problems construction $4,500 related to interconnection, planning by local offi- 1/2" messenger cable using line extenders cials should consider interconnection in conjunc- only $2,200 tion with service areas and distribution capacity. these combinations should then be evaluated in These savings can be achieved if the trunk cable, terms of present and proj?cted programming uses of the system, and plans should be oriented using line extenders, feeds subscribers directly. toward adequate capacity iv handle anticipated This eliminates added feeder cables and 3.cs3d- demands users will place on the system. ated bridger amplifiers. It is sufficient for radial distances of about two miles, feeding as many as 100 homes per mile, as long as the homes are WHAT CAN BE DONE TO within approximate 300 feet of the trunk. EXTEND SERVICE TO LESS DENSE AREAS? 'Before the development of transistors (and, more recently, integrated circuits), high performance requirements made Cable service cannot be economically feasible tube-type cable amplifiers very expensive. Cost savings were if there are not enough subscribers to keep the achieved by lowerii:g performance requirements for the feeder cable amplifiers (called line extenders). These amplifiers could shared cost of the cable distribution system low. be built to less stringent standards since they were not cas- In areas of low population density, cable service caded excessively on the numerous short lengths of feeder has often been economically infeasible in the past. cable. The savings achieved were substantial overall, since so New developments in amplifier technology permit many line extenders were used in a system. a decrease in per mile costs of distribution elec- The distortions introduced by transistorized trunk and feeder amplifiers are less than those generated in the finest tronics. In the future, as cable systems become tube type trunk amplifier a few years ago. Further, all modern technically more complex, the provision of service amplifiers have a new circuit design (called "push-pull") which to small or sparsely populated communities eliminates a complex kind of distortion and permits the use of additional frequencies outside the standard 12 VHF chan- '47 C.F.R. 74.901 et seq., (1972). nels. 29

Savings in capital cost per subscriber are impor- In addition, the FCC does not consider its tant to local officials only if they can be translated measurement procedures an adequate into lower subscriber rates, or provision of service guarantee that system performance standards to rural residents who live in sparsely populated will be met. The Rules require that each system areas that otherwise would not receive service. be tested annually, and that measurements be taken at three widely separated points. In its report, the commission stated: Many advised that requiring performance B. Technical Standards. measurements at only three vaguely defined points would fall short of rigorously testing A second area in which local officials should the system. Consideration has been given to make decisions is that of technical performance requiring measurements at more than three standards;' a malfunctioning system defeats the points in order to insure "representative" purpose of good planning and design. It is possi- sampling of system performance. But our ble to leave the enforcement of system perfor- view is that this requirement is not intended mance to the influence of the market place; the to establish that each subscriber will receive subscriber, who is the ultimate consumer of cable service in accordance with the standards that can come only with a measurement at service, may discontinue service if the quality of each subscriber terminal. The performance service is poor. Theoretically, if the system check is, rather, assurance to the operator operator begins to lose subscribers, he will make and to the Commission (should the perfor- attempts to improve the systems' performance. mance be questioned) that the signal path However, there are several reasons why the from headend to check point is capable of franchising authority should assume a role in the conforming to the standards. We are there- development and enforcement of technical stan- fore retaining the proposed requirement for dards. In the first place, the technical standards three measurement points. Many systems, as set by the Federal Communications Commission a matter of good practice, will make routine in Subpart K of the February, 1972 Cable Television observations at more than three points. The Report and Order are not considered comprehen- ultimate requirement, in any event, is that sive by the commission. Moreover, they do not the technical standards must be met at each subscriber terminal.' preclude the establishment of more restrictive requirements by local governments. In its recon- A franchising authority may wish to set forth sideration of the Report and Order, the commis- measurement procedures that give reasonable sion stated: assurance to local officials that standards are in The general question of federal pre-emption fact being met. of technical standards has been informally The establishment of technical standards by raised by a number of parties. Our technical local governments is desirable for other reasons. standards provide only a start. They will be The initial high signal quality may, over time, expanded to meet changes in the state of slowly degrade to a point where the signal quality the art. We see no reason why franchising is not completely acceptable. Subscribers who are authoritiesmay not now require more unhappy with the quality of service may not regard stringent technical standards than those in discontinuing service as an acceptable alternative, Subpart K.2 especially if off-air television reception in the com- Franchising authorities faced with decisions munity is poor. Furthermore, cable television's immediately may not wish to wait for further promise lies in its potential for public service; as commission deliberation. It should be noted this service grows, the franchising authority will that some states have already develowd techni- have a strong interest in the technical quality of cal standards for cable systems. rranchising services provided. authorities in those states should refer to such The franchising authority also has an interest regulations before developing their own in seeing that cable television facilities are safely technical standards. constructed and operated, and that the system's component parts are durable and reliable. Several federal agencies have set forth regulations that 'A guide for technical standards is developed more com- prehensively in Technical Standards and Specifications: Ordi- deal with such issues, but no comprehensive stan- nance Supplement Section VII. (Washington, D.C.: Cable dard for safety, ruggedness and reliability in cable 9-, Television Information Center, 1973.) television systems exists in one place. Therefore,

2Reconsideration of Cable Television Report and Order, 36 FCC 3Cable Television Report and Order, 36 FCC 2nd (1972) 2d 359 (1972). (emphasis supplied). 30

the franchising authority may choose to set forth permits). As such, those standards relating to the more comprehensive standards. quality of construction can be specified in the ordi- Finally, technical standards work no magic by nance though it is not necessary to do so. The themselves. A system operator has little incentive franchising authority may also want to examine to adhere to a comprehensive testing program if local codes to determine whether any of them his records are not examined by the franchising might affect cable. authority. In a letter to the president of a large The community's interest in construction stan- multiple system operator, the Chief of the FCC's dards for system reliability is based upon sub- Cable Television Bureau suggested the commis- scriber concerns that service be uninterrupted. sion's view of local governments' responsibilities Frequent system failure due to poor design, con- with regard to technical standards. struction, or equipment should not be tolerated The Commission will not, however, assume by the franchising authority, and can effectively responsibility for enforcement of more str- be prevented only by monitoring construction of ingent technical standards. Local authorities the system from the outset. Further, as public should therefore be prepared to assume the agencies make more and more use of the cable burden of such enforcement.' system, reliability of service becomes a direct con- Specifically, the center recommends a regulat- cern of local officials. ory program consisting of the following elements: Construction standards generally deal with Construction standards to insure a safe and those elements directly exposed to weather and reliable cable system the elements. Thus, provisions should be Technical standards for the reception of broad- developed for the following: cast television signals received either off-the-air Antennas protection against wind, ice load- or via microwave ing and corrosion Technical standards for ensuring overall sys- System grounding proper grounding of the tem performance power supply and metal components of the sys- Procedures for testing system performance to tem to ensure that the system is protected against ensure that all technical standards are being met lightning, power surges, and electrical interfer- The development of a record keeping log book ence that supports the technical standards and testing Arial cable plant provision to ensure that procedure programs. the cable is properly supported, that electronics are weatherproofed and protected from corrosion, and that equipment is accessible for CONSTRUCTION STANDARDS maintenance AND SPECIFICATIONS Underground cable plant provision to ensure Construction specifications for cable TV systems that conduit is rugged and large enough to permit focus upon two main elements: systenfsafety and adding cable in the future when it is needed. Provi- system reliability. A cable system which is sions to protect cable under heavily traveled road- designed to meet very high technical and performance standards can be ineffective if the antenna The substance of reliability and safety standards breaks the first time it snows or the amplifiers should be a comprehensive collection of relevant short out during the first rain. provisions from the National Bureau of Standards, The development of safety specifications in a the Federal Aviation Agency, state regulations, and cable TV ordinance permits the municipality to local provision for the use of the community's observe, check and.monitor and ensure system streets. safety. While this aspect of the ordinance is not Compliance for construction centers mainly on directly related to system performance and quality the monitoring of the system as it is built. There- of signal received, it is, nonetheless, important. after, the franchising authority's role diminishes. The construction of a cable system involves some degree of coordination and cooperation between such various municipal departments as highways STANDARDS FOR RECEPTION OF (rights of way)utilities (pole agreements), BROADCAST TELEVISION SIGNALS engineering (electrical standards), and federal OFF-THE-AIR OR VIA MICROWAVE agencies (e.g., Federal Aviation Agency for tower Cable television systems may meet very high performance standards yet still deliver low quality 'Letter from Sol Schildhause, Chief of Cable Television Bureau, Federal Communications Commission, to Edward M. Allen, pictures to subscribers. Broadcast television sign- August 11, 1972. als carried on the cable may be poor because the 31 headend antenna is badly situated, poorly headend, the system must deliver a specific stan- designed, badly installed, or because the televi- dard of signal quality to subscribers. Since stan- sion station broadcasting the signal is defective. dards for the acquisition of broadcast signals have From the subscriber's viewpoint, poor service already been defined, ordinance provisions for is poor service, regardless of the cause. The signal delivery standards should be developed to franchising authority, however, must be able to complete performance standards. pinpoint responsibility for poor performance. Standards for reception of broadcast signals PROCEDURES FOR TESTING THE SYSTEM define for a system operator the minimum quality TO ENSURE THAT STANDARDS ARE MET of the signal the system must secure with its antenna before it distributes the signal to sub- No standard has meaning unless procedures are scribers. These standards also provide a way of developed for its enforcement. The franchising grading the quality of each off-the-air signal authority should set forth reasonable and effective received, against which the performance of the procedures to test the ability of the cable system system in delivering that signal to subscribers can to meet prescribed technical standards. These be measured. procedures should be built around three kinds The first stop in defining specific standards for of tests. signal acquisition in a community is to require First, as a condition of the franchising that a signal survey be conducted. This survey agreement, the franchising authority might can be performed either by the municipality or require an initial, exhaustive, proof of perfor- by the system operator. In either case, it is done mance prior to the provision of service. The main to determine what television signals can be trunks should be tested without exception, and received, what quality of pictures to expect and parts of the feeder network selected at random. what possibilities there are for the headend Finally, a representative number of subscriber taps the desired site location, height of tower, antenna should be tested. The locations might be as fol- array designs and sources of interference. lows: Armed with results of a signal survey, the At the last trunk amplifier in widely separated franchising authority is in a position to require points in the system the system operator to place his antennas and At the last line extender in widely separated design them to receive the best quality of signal feeders of the system (feeders not fed by the trunk possible, given the character of local geography. tested above) - At multitap locations as selected at random to OVERALL SYSTEM PERFORMANCE provided coverage of the entire area. The purpose of the test in each case would be The FCC has set technical standards only for to build for the franchising authority a statistically the delivery of broadcast television signals by a sound "portrait" of the system's capability. Initial cable system. The commission expects soon to testing should occur with the completion of con- develop standards for cablecast programs, and struction of each section of the system and should ultimately, two-way communications. be tied to the construction timetable established In the meantime, effective performance stan- by the franchising authority. dards for broadcast television signal carriage is Many performance tests involve an interruption the most appropriate means for assuring that the of service. Once service has begun, tests which cable system is capable of doing what it is designed interrupt service should be conducted only as to do. often as is necessary to ensure that performance One way of defining performance standards is standards are maintained. A second kind of test to specify exactly how each component of the should take place once a year when the franchising cable system will perform, and to require the sys- authority should require the system operator to tem operator to install the specified equipment. ensure that the system complies with both FCC This is an unsatisfactory approach because it does and local performance standards. not guarantee the overall performance of the Finally, the franchising authority could require system. a series of monthly, inexpensive tests that do not A more effective approach is to require the sys- require the disabling of the system. Initial and tem to deliver a specified quality of signal to sub- annual tests can be prepared for, by judicious scribers, without specifying how it should do so. "tuning" of the system. An effective monthly test- The franchising authority can require that for a ing program should result in high quality system given grade of signal received at the cable system performance all the time. Monthly tests, con- 32 ducted by the system operator and reported to with the system operator for installation in the the franchising authority, provide a mechanism system of new technical capabilities. to ensure that the system operates near its rated In order to monitor state-of-the-art develop- capability. ments, many communities have formed citizen advisory commissions. The commissions are com- RECORDS TO BE KEPT prised of civic, technical and municipal leaders who periodically meet with the cable system man- The system operator should permanently main- agement and interested citizen groups to tain detailed records which show exactly how the exchange ideas and provide feedback to local system was constructed, in order to facilitate the legislative and administrative officials. modernization or overhaul of the system in the The example below from New York City illus- future. trates a similar approach. It provides a procedural Initial and annual proof of performance tests basis for making changes that consider both the should be evaluated by a competent engineer, consumer and the system operator. A cable com- preferably someone not involved with the system mission might perform the same function as New operator. Monthly tests should be examined by York's Director of Franchises. The required an agent of the franchising authority, but they are changes may involve heavy expenditures, so that likely to be simple enough to be interpreted by those responsible for technical review must not a layman, with assistance from the system only be familiar with the development of the operator. technology but also its usefulness to the com- Finally, the system operator should be required munity, and the costs involved. to keep a record of his responses to subscriber complaints, including tests made of what was After consultation with the Director of wrong and proof that the problem was satisfactor- Communications, if the Director of ily resolved. Franchises determines, giving due regard to Technical standards work no magic by them- technological limitations, that any part or all selves. A system operator has little incentive to of the System should be improved or adhere to a comprehensive testing program if his upgraded (including, without limitation, the records are not examined by the franchising increasing of channel capacity, the furnishing of improved converters, and the institution authority. of two-way transmission), he may order such improvement or upgrading of the System, to be effected by the Company within a reason- C. Role in the Evolution of able time thereafter. If the Company disputes any such determination or the reasonable Cable Technology time within which it is to be implemented, it may, within twenty (20) days after the Local officials planning for cable should keep issuance of such order, demand that the mat- in mind that they are dealing with a rapidly ter be arbitrated pursuant to Section 20 of developing technology. A system that is well- this contract. designed and meets high technical performance standards for today can become out-of-date tomorrow if the community does not provide Section 20. Arbitration adequate safeguards to ensure that the system can Matters which are expressly made arbi- evolve along with technology. System design trable under provisions of this contract shall should be such as to minimize obsolescence, and be determined by a panel of three arbitrators system operators should be encouraged to experi- appointed by the Presiding Justice of the ment with new technological innovations. Appellate Division of the Supreme Court of There are two essential ingredients to this the State of New York for the First Judicial process. First, the franchising authority should Department. The fees of the arbitrators shall develop the capacity to monitor independently be fixed by said Presiding Justice. The expenses of the arbitration, including the technological developments in cable communica- fees of the arbitrators, shall be borne by the tions. No procedural mechanism will protect the parties in such a manner as the arbitrators interests of the community. unless it is activated provide in their award, but in no event will by intelligent monitoring efforts by a specific the City be obligated for more than half the agency in the local government. expenses. The determination of a majority Second, there must be a procedure which gives of the arbitrators shall be binding on the the franchising authority the power to negotiate parties. In the event that an arbitrable matter 33

arises contemporaneously under another essentially efforts to both define and chart the franchise, involving the same issue as that future. to be arbitrated under this franchise,. the Cable television technology isno exception. Company will not claim or assert that it is Such abstract terms as "attenuation," "frequency prejudiced by or otherwise seek to prevent response," "second order distortion," and others or hinder, the presentation of the arbitrable do not inspire confidence in the minds of those matter under such other franchise for determination by a single panel. who must make decisions without the benefit of an engineering degree. Those terms evoke a fee- ling on the part of public officials that only technically trained experts can make technological decisions. III. CONCLUSION The reverse, however, may more often be the truth. Technological decisions are seldom purely In the future, cable must find markets for the technical rather, they concern our values, our new services that can be provided by current cable world view, our sense of the kind of society we technology and for those services that the emerg- wish to build. Decisions of this kind should be ing two-way cable technology will soon be capable made by responsible officials, not by technicians. of providing. Markets must be found in an arena This may be particularly true in the case of cable of competing telecommunications technologies television. Imbedded in seemingly technical deci- such as telephone, broadcast television, radio, sions about dual or single cable, converters or and specialized common carriers. switches, trunks, feeders, or drop lines,is the Nonetheless, there is little doubt that an impor- form of a new communications medium which tant role will develop for cable no matter what may affect in important ways the manner in which the ultimate configuration of urban telecommuni- we lead our lives. cations. More importantly, local officials cannot This report does not lighten the responsibility wait until the future is clear. Franchising decisions of decision making, nor does it make the decision which will establish the frame of reference for easier. What it does, hopefully, is explain the cable television development are being made aspects of cable technology with which decision now. makers should be familiar, point up the principal It is probably not too much of an exaggeration questions decision makers must confront, and to state that the public promise of cable television state alternative responses to these issues so that depends more upon the quality of franchising the opportunity for decision will not be lost. decisions than upon any. other single factor. An In the final analysis, we all must realize that understanding of the fundamentals of cable televi- technology drives us back to ourselves. It offers sion technology and its implications on design, wide choices for good or for bad. It expands technical performance, and future developments, our capacities but with effects we can never is vital to the quality of local decisions. completely comprehend. We must be as analytical Technological decisions are difficult to make as we can be in making such choices; but in the because they are complex and not easily under- long run our best guide to technological decisions stood; but, more fundamentally, because they are may be carefully considered human values.