DOCUMENT RESUME ED 115 303 IR 002 854 TITLE Cabletter; Numbers 1, 2, 4, and 6. INSTITUTION Connecticut Cable Coalition, Hartford.; Connecticut Univ., Storrs. Inst. of Public Service. PUB DATE 75 NOTE 28p. EDRS PRICE MF-$0.76 HC-$1.95 Plus Postage DESCRIPTORS *Cable Television; Closed Circuit Television; *Educational Television; Higher Education; Media Technology; *Programing (Broadcast); Social Services; *Telecommunication; *Television; Video Tape Recordings IDENTIFIERS CATV ABSTRACT Cabletter is an educational service designed to acquaint public service personnel in Connecticut with local telecommunications issues and answers. These four pamphlets include information on how cable television works and its use in the social services. Detailed information is given on how to develop your own 'television programing using portable video equipment. Specifications for the selection of video hardware are included. (DS) ****************************************************#**************** Documents acquired by ERIC include many informal unpublished * materials not available from other sources. ERIC makes every effort * * to, obtain the best copy available. Nevertheless, items of marginal * * reproducibility are often encountered and this affects the quality * * of the microfiche and hardcopy reproductions ERIC makes available * * via the ERIC Document Reproduction Service (EDRS). EDRS is not * responsible for the quality of the original document. Reproductions * * supplied by EDRS are the best that can be made from the original. *********************************************************************** 1U CABLETTER: Numbers 1, 2, 4 & 6. CABLETTER is a creation of the Institute of Public Service and the Connecticut Cable Coalition. Its distribution to Connecti cut public service personnel is an educational service intended to acquaint readers with local telecommunications issues and answers. kW, S DEPARTMENT OF HEALTH. EDUCATION & WELFARE NATIONAL INSTITUTE OF EDUCATION THIS DOCUMENT HAS BEENREPRO- DUCED EX"-, Y AS RECEIVED FROM THE PERS( R ORGANIZATION ORIGIN- cd ATING IT PL:,NTS OF VIEW OR OPINIONS STATED DO NOT NECESSARILYREPRE- SENT OFFICIAL NATIONAL INSTITUTEOF () OEDUCATION POSITION OR POLICY 2 a F.! [ ' I,11 t" ...ft'', A 1".1. I 1 \\ / \ 177'..:'-', I'..1 i,a INSTITUTE OF PUBLIC SERVICE e THE UNIVERSITY OF CONNECTICUT 3 A 2 HOW CABLE TELEVISION WORKS By Natasha Hertz summarized from Pilnick's and Baer's Cable TV: A Guide to the Technology. Cable Televisionisa communication system that distributes television signals and other information by wire rather than through the air. The signals are transmitted through a coaxial cable which can be laid in the ground or strung onto telephone poles.- T(ie cableitselfisjust one kind of information transmitter no different in principle from a telephone wireor a wireless communicationlinksuch -as broadcast radio or television. In each case, informa- tionis sent as a varying electrical signal generally superimposed on a high-frequency carrier. The higher the frequency of the signal, the more information the system can transmit. The advantages of using a coaxial cable are suchthat it allows for a much greater transmission of informa- tion flow which is why cable offers so many more television channels for entertainment, plus a large number of data services for health, education, and recreation. This also explains the difference between the terms "broadcasting" (which iSI.Ltilization of the air waves for information to reach a large, general audience) and "narrowcasting" (information directed at specialized audiences through awire). Aluminun1 (Ater Conduct og COPPER Clain -fhfrtihi Aluminuirn Wire- Cen-i-or C.OncitAt.+09... .. eta5tiicFoam Elements of a Conventional Cable System 1. Towers and Antennas 2. "Headend" 3. Cable distribution networks 4. TV Receivers (Home Cable Terminal) Natasha Hertz isa senior at The University of Connecticut majoring in Communication. After completing her undergradu- ate program, Ms. Flew plans to continue studies inurban planning and telecommunications. .05a-re Li. rrE. 3 Antennas CATV started in Pennsylvania as aresult of the poor reception people had because of theHills and moun- iins surrounding them.This is why the antennas which receive the TV broadcastsignals are usually located on one or more high towers.TV signals (which flow in a straight line) areblocked by the curvature of the earth orother obstacles such as mountains. Therefore, a sufficiently strongsignal will be received only where thereisan unrestricted line of-sight between a TVstation's transmitter and the cable system's antenna. Todaysatellites are used toreflectsignals back to earthfor transmitting (Telestar is an example), but their useis not wholly widespread. Headend From the cable antenna,each broadcast signalis connected by the cable tothe headend facility, usually located in a small building nearthe tower. In a city, thismight be the office building uponwhich the receiving tower ismounted. The headend contains all the equipment necessary to processthe signals for distribution on the cable network.The headend may also have other types ofequipment such as a small computer or automatedswitching system that will add the use of the computerinthe home for education, shopping, or homemanagement purposes. Itcouldalsointerconnect withother cable or computer systems anywhereinthe country and provide other special servicessuch as Pay TV. 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SwitchedSystemsDual-cable basicare three with systemschannels system converters other possible systems above the 6 Switched systems switched systems providea completely different approach to expanded channel capacity by placing channel selection outside the subscriber's home. The two principle switch systems under development are the AMECO DISCADE and the Rediffusion systems. Both bring signals from a headend to a switching center that serves from twenty to several hundred subscribers:Two separate wires are cables which run from the-switching center to each subscriber receiver. One wire carries sub- scriber requests to the switching center, while the other returns the selected TV signal. This brief explanation on ho'w cable works is just the beginning of understanding the many issues and potentials of cable. At present, there is a pressing need in two areas:1) To provide for the future of two-way cable systems, segrnentingneighborhoods for varying programming, and the selection ofspecial services... 2) Learning and obtaining advice pertaining to cost implications so as to be able todiscuss and control the cable company which has the franchise. Cab letteris a creation of the institute of Public Service and the Connecticut Cable Coalition. Its distribution to Connecti cut public service personnel is an educational service intended to acquaint readers