I • COMMUNICA TlONS • HOW ARD MARKS AND M. DA VID STONE
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ood dec io to somewhat more than 15 minutes~ 2.4QO. e sions require ·n bps rnodems to around 8 minutes. good ioforma· Wilhin lhe lasl 18 months. manufaclu r· tion-data th at ers have broughl 9,6OO·bps modems lo c a n be s peed· markel. This is nol equiprnent la be used il y galhered , simply 10 conneCI to CompuServe ar to plugged iOl o a chal wilh friends on a local bullelio board. repon. aod delivered lo lhe boss's desk . It is high·speed, high,cosl equ ipment. ahle \ Like desklop messeogers, PCs relrieve da· 10 send messages at four times lhe speed af 13-from hani disks and, wilh lhe help a 2,400·bps modem and bearing price tags frum a modem, fro m olher PCs. Ihal can lop$2,OOO . 1t is ideal forcorporale 15 PC-lO-PC communications pUI olher use, where people need lO send lruly large High-speed nwd.ems people's data with in our reach. minutes files-budgelary analyses, perhaps, or ali ;~ can transmit your files four away . They eliminate lhe inconveni ence oflasl year's fi gures on sales acti vily in lhe of producing repons lO be messengered 10 Wesl and Soulh. They are a1so good vehi· ,nd or even eight times olher locations, bUI-if lhe files you need eles for remate access to distaol comput are long-they a1so cao lie up lelephooe ers . minicomputer gateways and LAN lO faster than the modem lines and resuh in exorbitant telephone LAN bridges. you may now be using. bills. The 13 high-speed modems Ihal we re· Technology has broughl us a long way viewed-Ihe Cermetek 96OOE , lhe Codex frum lhe days of 300-bil·per·second mo 2260, Dala Race's PC-Race 24/96, lhe dems wheo seodiog a IOOK file woul d tie Faslcomm 2496-T, lhe Gandalf Access up lhe phone lioe for more Ihan 50 mio· Series V.32. lhe Hayes V-Series Sman 02 ules. The 1, 200-bps modems CUI Ihal time modem 9600, lhe Microcom AX/9624c,
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P C M A G A Z I N E • A P R I L 2 b. I 9 8 8 105 ,. IflGH-SPEED MODEMS
lhe Racal-Vadic 9600VP, ',elebil's Trail a technical and scientific standards group dem, Ihey mUSI be echoed back along lhe Blazer Plus. lhe Telenelics 96OOE, Uni based in Europe. sarne line 50 Ihal lhe modem will recagnize ve=i Data Syslems' UDS V. 32, U.S. Ihat lhe data arrived safely. However, lhe RobOlics' Courier HST .•nd Ven-Tel's WEIGHfOFLAW Although CCITT V.32 modem musl be able lo recagnize Palhfinder 18K-were .11 compalible aetivities are technicaJly called "recam Ihal lhe echoes are echoes and nOl incom enough 10 be used wilh PC lelecommuni mendations" rather than "slandards," ing data. For Ihis reason, lhe V.32 mo calions software Ihal supports lhe Hayes Ihey often have lhe impact of law. Mem dems require special echo-cancellation cir A T command seI. The produclS range in bers of lhe cem are national govern cuilS Ihal leI lhe modem keep tmck of price from $795 to $2,095. ments; in most European countries tele what's been sem, compare it wilh what's phone syslems are governrnent cornlng in. screen DUl lhe echo. and re· IN TIIE BEGINNING Codex made lhe monopolies, and il is aClually illegal in ceive only lhe data Ihat was inlended for fLJ'S19.600-bps modem. 1I appeared in lhe some countries to use modems lhat don '( Ü-nOl a copy ofwhal iljusl sento This cir early 1980s, sold for abouI $10,000, and f ollow cem recommendations. cuitry adds about $500 lO lhe cosI. was designed for mainframe communica r- In an effon lO produce affordable high tions. 1I is wilhin lhe lasl year and a half speed prodUClS for lhe PC mmel, modem Ihal high-speed, 9,600-bps modems have manufaclurers have developed several in become affordable and pracrical for PC • Within the last year genious-and incompatible--approaches communic3tions. BUI attempling 10 lhat use less-expensive modulation choose lhe righl one certainly can be a dif and a half, 9,60ü· schemes lo emulale full- P C M A G A Z 1 N E • A P R 1 L 2 6, I 9 8 8 106 ~ • • GLOSSARY~·OFXERMS ASYMMETRICAL MODULATION OIECKSVM·A method of describing ,then transmit An example wou1d be a The process. through which a modem ,;8 block of·data~calculatedby,adding ali two-way nulio system, in which the op. working in a full-duplex environment -~the bytes in the block together and taking ~r says ~~ver't 10 signal theother op. willsimul~eously transmit data in1Wo 1he low-order'(right-side) :16 bits. This eratorto speak. ·directi~ aí aifferent:speeds. An uym-.: ':.method will.detect-,single-bit errorsarid metrical modem:.mayoffer bigh-speed: ·~memultiple-bit. . '.':~:':. UNE ·I1JRNAROUND . On 'a:.half-du- qansmission in one direction, low-speed c, plex connection, 1he process ofchanging in the other. -CPS Characters ':per ·secand. '1Another the direction in which data is being trans- ,measure of.:the.speed -of a communica- .. " mitted. BAUD A state transition between. ..two, ~tions-device.'UsuallyiO.hitsF'charac~): " distinguisliable·nominal :~a1ues;«)n: ;.the ....: :;';fer·is 'the}7Standard'inr~"communica.;~~':PlNG-PONG )~A 'method of,full-duplex communicatioDs1ine,orthe ·nuni~~of<~ ~:;1ions ..(althouglf9 .. bits.:per ~r:may '-~:~;.·emUlation OD llhàlf-duplex link that pro thesetransitions'per·=second.~';tbiS·.; ~... ij]eusedforhigb-speedtransmissions.·J~: ':Mdesantomatictinetumaround'whenthe tenn is often used to mean bits per second ; . .' . " .' : . ~~l! ~receiving ~modem.has·outgoing •.data to (bps) , .each. transition 'may:represen't} áCRC 1,Cyelical redundancy cheek"" ~1 '1ransmit. .' more·than 1 bit1be misuse.arises ·be- .' ~more sophisticatedmethod-of describing '.: cause on'a ·standard ~232 iinterface,,-matathanchecksum.T.his method iS':i 'V.n:::The-OCI1T"standard for 1,200- each transition represents'one bit. .more accuratein· detecting multiple-bit . bps full-duplex modems. " eJlOrs. BELL 103 ;'The ~erican standanl for, :';', V.n BIS ~e :CCITI 'standard for 3()();bps full-duplex modems, developed' ~D1E SPEED .(f:Data terminalequipment i.'; 2~400-bps full-duplex modems. by AT&T prior to a mid.;1970s FCO rul- ;:::speed.'. The 'maximUD) ;:speed -.each· mO-::.:,· . ing pennitting competition by other man- ,,~' dem will accept datafrom its host com- '. V.l5 . The CCl1T standard of.auto-dial , ufacturers of communications products .. ' puter.lt is represented in bits persecond. :.. ' .commands for modems.and other auto- .' . -'dial devices. Not often used in theUnited ' 'BEÍL m 'The Americail standard for: . :FlJU.DUPLEX ":';Allowing simulta-. States due to the popularity of the Hayes 'l,200-bpsfull-duplexmodems. . neous ·.transmission in both ,()irectiODS. _ATcommandset. : ~ The telephone is an example of a full-du- - ~. BPS;;iBits per.second;A measure ofthe : ... plex communications ~stem. c :'V29: :The CCITr 'standard .Ior~9~600-' speedofacommunicationsdevice ..~~ " bps half-duplexmodems,.;alsQ:;usedin IIALF-DUPLEX ·Allowing communi- facsimile machines.. . , .' ,~~'-' .... éAmuER A tone of a specified fre cation in both directions-butin only one :'~:' queney that is modified per bit value for ;·direction ata time. Half-duplex systems . ,V.32 ,The cCrrr standard i~,'9.600-·. sending data via modem. A modem with must have a method of letting the receiv- bps full-duplex modems ,DOt 'widely a Canier frequency of 300 Hz might send ing end know that the transmitting end is· 'used for PCmodems due to cost.~·, ' 320 Hz tone for a 1,and 280 Hz fora O. .cfinished, so that.thereceiving,end can ··~·~HowardMarks .. ~~.: '. modems with asymmetrical modulation Asymmetrieal modems theoretically to tom the line around quickly. schemes that provide a 9,600-bps balf-du perform better than ping-pong modems in Both Telebit's TrailBlazer Plus and plex ~ta path and a low-speed (typically two types of applications. The first is pro Ven-Tel's Pathfinder 18K, whieh uses Te 200-1 ,200-bps) data path in the reverse di tocol fIle transfers, in which the data trav lebit technology, follow a unique multicar rection, often ca11ed the "reverse ehan- eis on the high-speed forward channeI and rier modulation scheme that theoretica1ly ! nel." the acknowledgment packet takes lhe low makes the most of the available band U.S. Robotics' Courier HST' s and lhe speed reverse ehannel. The second is inter width. Rather than use one canier frequen PC-Race 24/96's interactive made, use active queries, like airline ticketing, in cy and heavily modulate it to cany 4- or 5- asymmetrical modulation. The Hayes V whieh keystrokes take the reverse ehannel bit-per-state transition (baud) and many Series Smartmodem 9600 uses lhe same and screens of data travei on the forward ttansitions per second, TeIebit ehose to di modulation scheme' as do V.32 modems, ehannel. In reallife the reverse channel is vide the available line bandwidth into a but in a ping-pong fashion, avoiding the often too slow to handle some applica 1arge mmlber of caniers, whereby each cost of echo-cance11ation circui1Iy . tions, so it is also important for the modem carries a small amount of data. When two P C M A G A Z I N E .• A P R I L 2 6. I 9 8 8 107 • HIGH-SPEED MODEMS ~ High-Speed-Modem Protocols igh·speed modems send and rec:eive data using three basie ping·pong protocol, data will travei in &ilhar direction aI lhe fast rate Hprolocols: V.32 lull-duplex. esymmelrical. and ping·pong. Wilh Df 9,600 bps--but lhe modems cannat share lhe tine. Data moves i lhe V.32 full-duplex protoool, two modems can exchange data aI a only cne direction ai a time, but lhe modems will quickly reverse tht rate of.9.6oo bits per second in both directions aI lhe sarna time. 11 direction Df transmission, ar tum lhe fine , when lhe receiving modar works much like a telephone; two people can talk at the sarna lime. has data to transmito This process is comparable to Ihat cf two-way Asymmetrical protocol allows lhe sending modem to transmrt a file aI radio oommunications, in which only cne radio operator can speak a rate of 9 ,600 bps; aI lhe same lime, lhe receiving modem is able to • on a single frequency::a.t a time. transmn dala back lo lhe sender only ai a rale 01 300 bps. Wilh lhe V.32 FULL-DUPLEX PROTOCOL I _...... _-,.~--.---... ,...... ,...... -_._~. ~ .Data moves 8t 9,600 bps Receiver ~ Data moves 8t 9,600 bps . ... :. ~ .. ,":.• ' '" ..... ~. ~. .' -•.: .•-~", >.- ~ , .. ' PC MAGAZINE. APR IL2 6. 1 988 108 , , modems using lhis technology connecl, look at lhese modems. The best of lhem they send lones aemss lhe line and deter work wel! ai most tasks--and any of lhem !tl~ mine which of 500 possible carrim can be save bours when trdOsfenring large files. used on lhe phone line in each direction. However, don'l expecl lhat what you buy ~ FACT F I L E From lhere on, lhe modems use lhose car will become an industJy standard. Many of . "Camettk 9600E riers and emulate full- Lf you have an irrunediate need for higb- The Cermelek 9600E anti lhe TeJenelics 96fXJE are idenlical e.xceptfor Iheir names. They have a L~ex~i=st=in_g=2=400~=.speed communications.==~==~~ do take==~~~~ a dose __simplisli~ ____c des~~ ign odi __sfin~ guished ____ by~ two ______wide rows~ of coo__~~lin g venlS ______aI lhe lOp~ ofthe~ ____ cabi______nel. ~ 1 P C M A G A Z I N E • A P R I L 2 6. I 9 8 8 109 • IDGH-SPEED MODEMS The 9600E uses a cuslomized LAP-B could henefil greatly from examples. (Link Aeeess Prolocol-Balaneed) error OveraIl, lhe problems wilh lhe RS-232 ~ eorrection prolocol wilh a I 6-bil éRc (ey interface oUlweigh alI lhe positive fealUres clicai redundaney eheck) and a maximum of lhe 96OOE. A PC user shouldn 'I have 10 ~C FACT F I L E block sire of 128 bytes. Unlike mOSI error cuslomize his communications software -êocIu"2UO correcting modems, lhe 9600E was as re jusl to make it work with a mo QKlexeoq,. sponsive with enurcorrection rwned 00 as dem.-Howard Marks 7Blueliílt RiYe.-lld. il was wilh il disabled. Can1oo, MA.()2021 One nice fealure of lhe 9600E is ils in (617) 364-2000 CODEXCORP. .J...ist PrIce: SI,995 lemal power supply. 1\ comes as a standand Requlres: R$..232.cabIe. powereond, nOloneoflhe huge wall-trans Codex2260 lnSbort: A rugged V.32JTItldeiUiax>m fonner varicties thal many rncx1em manu lI's casy lo see from lhe Codex 2260 Ihal meniIcd for fac:torieo anil othor hóstile ..vi". faelUrers use. The fronl panel has LEOs for Codex Corpois serious about data eommu ronmcnlS.J'iia:d wcIl buldoeSn"suppon )ow.-spocd opendioojll a1so larJcs;crror-cor data lerminal ready (DTR), modem ready, nications. Wilh its large size, lhe protec _ anil da!a oompressioo. transmined data, reeeived data, high tive door over ilS contrOls, and its olive· 'CRl:EtI7OHfEADERS8MCECARD speed , error coITeCrion 00, and modem drab paint job, lhe 2260 is an impressive eheck (whieh flashes if Ihere are any data piece of handware wilh a military look retransmissions). The 9600E also has push aboul il. Itlists for $1 ,995. 115 performance. like Ihal of lhe olher bunons lO answer and can manually origi In facI lhe 2260 is larger (16 by 8'12 by true V.32 modems in our tesl group , was nale a call1hal is already dialed, ean force 33/, inches). heavier (o ver 8 pounds), similarly impressive. No matter what we 4,800 bps for noisy Iines, and ean enable and--duc to its internaJ fan--noisierthan a \hrew aI lhe 2260, il juS! went its merry error correction . TI 000 laplOp computer. 115 internai struc way-transmitting ils dala aI 9,600 bps The 9600Es support only high-speed IU re is more like Ihal of a computer lhan a wilhoul skipping a bil. While lhe pseudo commu nications, 50 you 'li need to have a modem. IL has a separale power supply, full-duplex modems wilh data eompres second modem for low-speed applications cand cage, and a fan. sion can go fasler on a clean line, lhe like calling MCI Mai!. Cermetek has an nounced a new model-the 96OOFR-thal will add 300-, 1,200-, and 2,400-bps com munieations lo lhe 96OOE. The 9600E supportS lhe basie Hayes Smartmodem 1200 AT command sei, bul Ihere were problems wilh almosl ' every communicati ons package tested 0 0 it . The -problem is in lhe way Ihal Cermelek han dles some oflhe RS-232 eontrollines-by Iying earrier delecl (CO), data set ready (DSR), and dearto send (CTS) logelherso Ihey ali go high or low aI lhe same time. Mosl communieations paekages expecl OSR or CTS 10 he high hefore Ihey send eommands 10 lhe modem, and Ihen expecl CO 10 go high when lhe two modems have established a connection. On lhe 9600E you ean seI a OlP switeh lo make alllhree lines high ali lhe time (making your soft ware Ihink Ihere a1ready is a eonnection) or go high when lhe two modems are con nected (preventing your software from sending eommands lo lhe modem). Com plieating lhe siluation, lhe follow carrier delecl position is labeled "normal" in lhe manual. Carbon Capy's memory-resident module won 't even load if CTS is low. Telenetics's documentation seemed a bil casier to understand Ihan lhe Cerrnetek Thefroru panel ofIM Codex 2260 ean be apened./nsiáe is an LCD anti push bUlIOns lhat leI you sei manual, but bolh of Ihem are terse and lhe modem' Soperaling modes withoul software or DIP switches. PC MAGAZINE. APRIL26.1988 110 • IDGH-SPEED MODEMS 2260's noisy line perfonnance was tlaw factO!y and need good interactive perfor less-even on lines lhe pseudo-full-duplex mance, you should consider lhe 2260. modems failed to work on at alI. However, lhe 2260 doesn't support low rrH In real-world USé, lhe !rue full-duplex speed operation and doesn'l have error ~ FA CT F I L E nature of lhe 2260 makes it perfecl for in correction ar data compression-the price PC-Ra P C M A G A Z I N E • A P R J L 2 6, t 9 8 8 ll2 • IDGH-SPEED MODEMS EAS\' SEnJP . The PC-Race is made up real-world use, these delays shouldn 'I be of a mOlherboard and two modem mod especiaHy bothersome in interactive ules-one each for lhe low-speed and mode. In block mode lhey weren 't as bad !Jllol high-speed modems. PC-Race is a full-slol as some af the other rnooems in our tests, ~ FA C T F I L E piggybacked card-but it's nOl 50 lhick as bUI lhe delays were a bil disconcerting, FastrommU96-T to interfere wilh adjacent cards. Selting up with characlcrs oflen appearing on lhe Faslooinm GommunitaUons (Jarp. lhe PC-Race is a breeze. Insuuctions for seree" in clumps. 1'Z34'1.<1'Sumise v~ Or . ali swilches and j umpelS are printed righl Puning a good inleractive mode and a .ResIan, VA.22091 (703) 6JO'3900 on lhe modem. Vou can buy lhe PC-Race good block-tnmsfer mode in lhe sasne m0- ·,LIstPiióe: $1,Q!!9.Intemal-=iõn, SI,fw,) dem and chasging a reasonable price for wilh bolh high· and low-speed modems in· .Reqüires:!BM- made screens appear in fits and starts, receive the acknowledgment. when compared with the other models re since the modem had to tum the line The Fastcomm manual is better than viewed here.-Howanl Marks around to send the acknowledgment pack average and includes directions -on setting ets for its proprietmy LAP-B-based (Link up popular PC communications pack GANDALFDATAINC. Access Protocol-Balanced) el1Or-correc ages-including Crosstalk XVI. Relay tion scheme. Gold, Carbon Copy, and Blast--for lhe Gandalf Access The Fastcomm line tumaround is so 2496-T. Fastcomm provides a copy of Series V.32 slow because lhe two modems must tIain, Qmodem. one of the more-powerful The Gandalf Access Series V.32 does or adjust, themselves to lhe quality of lhe sbareware communications packages, things well but always in its own way. One et:-'f!5ª,lhwM~J.fl.);,*Ai$~Ü~ wilh their PC and external models. of lhe few V.32 modems that also supports The 2496-T is a "Hayes-compatible" low-speed communications, it also uses 2,400-bit-per-second modem, and Fast the cem V.25 command set (a trait pn • The FastcolIllil comm aIso makes a 2,400-bps modem that usual in a modem). can be upgraded to the 2496, as well as a Like the restofthe V.32 modems in our 2496-T' s tumaround is so 9,6OO-bps-on1y version that can be field test sample, the Gandalf perfonned flaw upgraded to bave ali the 2496 features. The lessly 00 OUI' noise tests and echoed cbar sIow that some Xmodem 2496 supports lhe basic Hayes command acters 00 the character turnaround test so set from the Hayes Smartmodem 1200 and quickly that you would have to set a new implementations may time has several additional commands that are world record in typing speed to notice any implemented differently than on Hayes ~s delay, allhough some of lhe modems with out before they receive newer models. I had no problems using the data compression were faster in ttansmit Fastcomm as a nonnal modem except 00 tingdata. the acknowledgment. Hayes's Smartcom-which assumes that a Smaller than most of its V.32 competi 2,4(X)-bps modem supports the full Hayes tors, the Access Series V .32 has four rock Smartmodem 2400 command set. er switches and ten LEDs on its fioot pan line each time the Iioe is tumed around. Unfonunately, neither the data-com el. There are LEDs for power, transmilte(j This training takes about a quarter of a sec pression nor error-correctioo features of and received data, clear to send .(CTS), ond-and if you have error correction the 2496 work wheo using the modem at canier detect (CD), data tenninal read) tumed on, the line must be tumed several lower speeds. (DTR), offhook, auto-answer (which alsc times for each echo. In our testsit took flashes when the phone is ringing), el10l over a secood and a half for each character NEW MODEL DIJE SOON Fastcomm control (which is lit in error-correctior to be echoed.1n reallife you'll find your could improve this product without too mode), and test status. charactet'S echoed in bunches. much etTort by adding MNP enor correc tion to the 2,400-bps mode, and by making SWITCH CONTROIS The switche~ SLow CONNECI10N The Fastcomm -the modems drop down to 2,400-bps mode control the modem's self-test features also takes a while to get connected (up to during interactive type processing-there switch it between voice and data mode 30 seconds in our tests), so you may need by eliminating the tenible character tum and select any of its three command se to adjust your software to wait forthe cani around delay. Since it uses the same mod modes. Mode 1 sets up the modem as ~ er longer lhan you would for a. standard ulatioo scheme as fax machines anyway, low-speed, 2,400-bps, Hayes AT com modem. Fastcomm could also seU software to allow mand-set-compatible device. Mode 2 i: Since the Fastcomm was specifically you to send faxeS using your modem. designed for file transfers, it performs The 2496-T is available in a half-card them much better than a general-purpose PC bus internal~ externai, and rack-mount fITiJ modem. Its data compression really helps versions. Fastcomm has also announced a ... FACT F I L E move the data sent over 1,000 characters new model that uses asymmetrical com per seéond 00 a petfect line. The line tum munications like the U .S. Robotics or Data around problem reappears when we use a Race interactive mode. This should be file-ttansfer prótocol; throughput drops to much better at interactive operation and just 76 cps ü we use Xmodem-Iike 128- standard protocol transfers. byte blocks and to 414 cps with a IK block Unless you have an installed base of protocol. Fastcomm users should just use Fastcomm modems or special file-transfer protocols like Ymodem-G orZmodem that applications that don ~t require operator in send data back on1y ü there is an error. In teraction, you should look at olher mo fact, the Fastcomm 2496-T's túrnaround is dems before the Fastcomm. Its slow line so slow that some Xmodem implementa turnaround and lack of standard el1Or-cor tions may time-out before they are able to rection protocol make it a poor choice P C M A G A Z I N E • A P R I L 2 6, 1 9 8 8 116 • HIGH-SPEED MODEMS HAYESMaCROCOMPUTER PRODUcrS INe. Hayes V-Series Smartmodem 9600 The Hayes V-Senes Smartmodem 9600 is a relalive newcomer among high-speed modems. Being from Hayes, however. il's also the one with which olhe" inevitably will be compared. On some poims, as you mighl expecl, the Smanmodem scores well indeed. Even on its weakesl points. it scores well enough. One oflhe $1.299 Smartmodem 9600's beSI points is ease of use. While every me> dem in today's PC markel cJaims Hayes compatibility. some are more compatible Ihan olhe". Their differences can translale imo problems in installation-- P C M A G A Z I N E • A P R I L 2 6. I 9 8 8 11 8 ' Hign-Speed Modems: Summary ofFeafures (Products lisled in ascending ptice O 1]] UDSV.32 C.rm.tak t600E GandIU_" Pattlflndef 18K Untversal' Cermelek'Micro- COllo2260 T,leneUCI HOIE $trlosV.32 Ven-Tellnc. Data 5ystems electronlcs I~. CodexCOrp. Te!'nolk:s Corp. Gandalf Data Inc. LOWSPEEDS $1,399 '$1,595 $1,995 st995 .St.995 $2,095 300 bp. • O O O O • 1,200-bp.8'11212 • O O O O • 2,40o.bps V.22 bis • O O O O • TOPSPEEDS Dali compre ..lon O O O Q O Flllblck (bpl) •In 200-bps None 4,800 4,800 4, 800 4,81l1l Increments fali forwlrd O O Mlllmum DTE Iplld (bp,) 19,200 9,600 •9.6 00 •9,600 . •9,600 9•,600 DIP ,.lIehel O O • O • O Fronl-plnel eonlrol O • O • O • HA VES COMPATIBILITY 1200 (orlg lnl l commlnd lei) • • O • O • 2400 lextended command sei) O • O O O O Dl lll ng eommlndl only O O O • O ERROR-CORRECTING • PROTOCOL Hlgh Ip.ed Proprietary V.32 Proprietary None Proprietary Lo.apeed (2,400 bpllnd MNPClass3 None None None None PC MAGAZ IN E . APRIL2' 6, 19 88 11 9 • fDGH-SPEED MODEMS Error correction in the Smartmodem 9600 uses a proprietary enhancement to the CCITT LAP-8 (Link Access Prolocol- 8a1anced) error-<:orrection prolocol. Thc data compression scheme is also propn ewry . UNSHARED STANDARD What's nice is thal the modem can use error correction and dala compression aI 2.400 and 1.200 bps while talking to the Hayes V-Senes Smanrnodem 2400 or a standard externai Smanmodem equipped wilh lhe Hayes V Senes Modem Enhancer. Alas. lhe com pany so far has chosen \O keep this scheme 10 itself, thereby ruling out the possibility lhal il may become an industry-wide S!an dardo In addition to talking lo olher V-Senes modems ai slower speeds. lhe Smartmo dcm 9600 can lalk to mOSI Olher modems using 8ell 103 prolocol ai O to 300 bps_ 8ell 212 or V .22 prolocol ai 1.200 bps. OI V.22 bis a! 2,400 bps. AI 4_800 and 9.600 bps. lhe modem uses a half-duplex varia tion on V.32 prolOCOI. Hayes kepllO itsfamiliardesign wiIh lhe V·Series Smanmodem 9600. Thefront pane! spons lh e When establishing a Iink. the modem some seI ofstatus lighls as do olher Hayes modems. Th ere are no vems. takes abauI 13 seconds 10 negOl!atc the speed of the link and lhe presence or ab sence of data-compression and enor-cor switches; it srares a11 modem settings in dard , single-line desk phone. recting prolocols. This period is long nonvolatile memory. More importanL, il The modem's front panel sports the enough tha! you may need 10 adjusI lhe has essentially lhe same command set, so same seI of status lighls as do olher Hayes amount of lime your prognun waits before lhat any prograrn designed for lhe Hayes modems: modem ready (basically a pow deciding lo cancel a call. No capabiliry ex 2400 should work with lhe Hayes 9600. er-on Iight), tenninal ready, receive data, iSlS 10 adJusI the speed of lhe transfer dur Dunng testing, the 9600 worked swim send data, off hook (lhe modem has picked ing a session to compensate for chang in ~ mingly with Relay Gold and Crosslalk up lhe phone), carrierdelect (lhe modem is line conditions. Mk.4, set for the Smartmodem 2400. As talking la another modem), auto-answer, _On lhe PC Labs speed lesl: lhe Smart· expected, it also worked wilh ProComm , and high speed. modem managed a respeclable 1.12S Crosstalk XVI, Smancom 1/, and Smarl BUI aoe shoncoming here concems the cps-which placed il well below the 1,531 com 111 . high-speed lighl--{)r ralher lhe lack of ad- . cps for Telebit's TrailBlazer. In lhe PC Anolher plus is lhe modem's speedy ditional speed lighlS. The light comes on 10 Labs Xmodem test , lhe Smartmoderr turnaround time. The 9600 managed a indicale a 9,600- or 19,200-bil-per-second ranked in lhe middle of lhe pack bUI re· character tumaround rime af 112 míllisec• conneclion to lhe computer. Ideally. it mained ahead of everylhing else cxcepl lh, onds-abaut '/ 10 second. The only faster would be helpful to know which speed lhe full-nedged, fu ll -duplex V .32 modems. times were for lhe more expensive, fuH modem is using. On noise LCsts, lhe Smanrnodem agair nedged V.32 modems. A)so troublesome is thal no indicalor scored respeclably bUI nOI spectacularly distinguishes belween a 2,400-bps and a failing only when facing a more-lhan-aver· SIMDAR APPEARANCE Physically, 1,200-bps conneclion. The modem can be age amount of noise on a worse-than-aver lhe Smartmodem 9600 is abaut 'I, inch set to repo" lhe speed when establishing age line. taller than lhe Smartmodem 2400. Olher lhe link, bUI with some prograrns you have Ali lold, lhe Smartmodem 9600 is ex wise they are nearly identical-so much so lO rum off this fearure to avoid confusing actly what you -d expecl from a compan) lhat you might not notice the difference if lhe software. of Hayes's stature. lt 's a reliable unil witl lhe label 9600 wasn 't wnnen on lhe front As do olher high-speed modems, lhe respectable performance and a high degre< panel. As with olher Smartmodems, lhe Smartmodem 9600 has built-Ín error-ror of compatibility wilh earlier Hayes mo unit is just lhe nght size to fit under a s!an- reclion and data-compression schemes. dems. Thal, plus Hayes's well-deserv", PC MAGAZINE. APRIL26, 1988 130 • ffiGH-SPEED M6DEMS reputation fop support, may be enough 10 make lheSmartmodem 9600 your modem of choice.- M. David Slooe MICROCOM INC. MicrocomAXI9624c As mighl be eJ9l"Cted from lhe inventolS of lhe ~icrocom "Networkil!& Prolocõ! (MNP), lhe Microcom AXJ9624c uses fue lalesl MNP Class 6 for full- w~fr1:i~~l"~,r.~.·~·.~.{~r~~~~i~~~~I;~~i,,,,,:.:.,~~?:~!~~:-~,~':"~.,-=,., .. =-" ~- ~~:I'; ':,. ~ _:_ ,.,=:_~"_,'.'• .> ..A ti nigh-speed modemS.are'rnot.created equal;~ these.: :<:.S96,'fubOttl· ' , . '. betteimthe~odem ·.!i~testIel?ults'd~onstrate;Thestandard:V.s2modems':'~·~:~,:·*~t;·1ankiruijústbe1lindH~Yes~-.and~Microcom·s.modems. '~~m-UnJversal Datà·Systems.~rmetek,:Codex/GandaH.; ..~' '::::~;'~ <. <:';.:~~ ~:'::;: :.-: ~. :.... ~<.: .>'. ,~'.-:.~."-':'<" .::-;;::- ....~ ,:'<' .~:~<,.~' . ::7:)anarelerietics à11·pérformed.about the·sarne;. but the.pseudó-~f~n~~úglipútlestS;tbose:j)sEnjdo~fLil1~uPlex mOdems ·~.t1ut1-dlJplex~odem~~uplexones that ernu1ate:Jull-.·P~.íi~{tf~ff~rjruJ·:à:lla co~Pr~io~ .as:ielebit's l:râilBlazer .. ' :'~uplexthrOugh:a.MrfuallY~Íldisting"ishableTUle·tüniárourí~·~?~lus~~~~opôti~~ü~~ST4:an~the Hayes"V-:Series ',1-;were Ym.Ylflffe~irom-eaCh-olherêJ1d ãlffereiJtfrom ~e; <:~:~~,;...:s~nl:9.600=:starta.{outby~mlttir:Jg data.~pto50 .t"0J0í;;5~~~f~"~~::,,~C.- - ...... >__ ;;,k]!r_·':::i:i~~~l;~~4~~~i:~ngo -.~Mm. o.nR.lhe.. ~I~.. ~. t.h.d. llPl. ex·moda.... msttbe!l@YB.. s.v~s. e ... n ...~~.:r.'--~~.~i,t:;.i< .. -:,,~.~.';:""::1'\'_':" g ... 9'.. , ..i';.t.~,;;,..·:~<.~;.....:.,"!.~~ ••. ~ii..-.'~";.·~.'~": :~'1!z.·: .. -.)~.:~~.... :: . ·{~~~~VacrDc:ôÕl~~~.éÍBbií'S~~~3.~~~i1Õ;;~ 'B1Sô~diid.âràinãt1êãí&~~~-·;~2fóisi ~íhOne-1ines :~"~iai1BIazéf.~spapdNe~e.r~:r.~~~~K~~jJôf:~tiÓ~W~~ã~.~~~~1tl ?!'the·qu81l!y·;of.th~1.~II~plex:emi11áticmi8sTepf8sentédjr~ê~é~êT~t~~1~p;o:~---coPl.Of~~~~~iun,;(fup1ex ':::;', .~ • r:~haradér2r.umároündteslS;~blleperformances·:Ol1hÊftl~;.·{}f~0d~~~~~~ifi~~~~tS1~~;.~djaiJed:tó. ':--;.Fastco~m2~96::r~PataRaée1s"f!!rBace24/96were.':\~f:~tr;mansrriit~r~~iSe~~~lhà~âr~plittir)iri8vels ;",.specifiedbyiAT&T«cérr.r~}r.:'fjJ!lgôCominunlêats1imlngb\1urmatiDn,,;, .. ,r~~,~aridtheiiiodeml&throughpUt.as :t~~>-::~;.;.: •.: ·~'·~'~I.P!;J;'f:,\~;~\,:~' .> .. ~1i,';'~.. '-"; g$~~~l~~ª~~~~~~r~'·:~~~:~f~lil~·;~- .j.,netwoI1t'sllm1tedbandwlcfttl:..".,approach·':""~anyposslbllity-ofdel8y•. Themaster.~strBam'DfJdenticalCharaders,~".;r~., .' , .. ,'0;," ',. :~; ...'...... :::~~-~~~;::~~:lª~~~t~l;ji~~:~I}~·l~~', Some modelsafso1mpRwe throughputby ·~ .. mediatetyechoGdllbackto1hemaster·The· --lestmeaSuradhow:WBll1he'inodems ,..~,;;.;.,-, •. ,~'-:i~;r.'!1.-·,." "-. .~.,. ~";' ~j}~1~~~P-jjj~i~it,.ji - needtotestwhetherthefulkluplex< ·.:·~'~,~···:,-·~:~purchasingofficer.·After "-.' 9,6OO-bit-per-secondmodBmsprovide ~'- ,- .- ~ , - emula!lon wort • o --erram we.naver made. We a!so need to : '.:9lOBf8J lndica1ion cf how weD 1he pseudo- .. #'.!,-';". : . 0xamIne bowwell 1he da1a COInpession . - .. ,<1uIJ.dupIex modems pertcnn their fuD.dupIex l' " ".";rSnd error.c:omJCtion wortc.and howweD lhe .: .. emu!ation. ;:- ", .... -' : ,-.";:.- -~" ~:;...G1Od6m's 1t1roughput ia impedocI b'jtlOisy ' .. '.:' . ~~~2:~~:r'-·~·:;,"';~'·~'::~:·:·:;' .... ~ .:~:·,,::,:;·;~;~.::~:fi~~~:~~:~~~·.:;t~:~}}fF·o:'-. ~~ ... , \ ': :'-';H:~-;.----.. _, o'!.:;," :... .-~.;~ .~ ".-" .:; ! . . -- '" ',' .··:~·~::;/i0~·;.: :'\'~::;:S~~~~:" . . ... " ~ .. - . ..:;.- ....:~ .. _.~ P C M A G A Z I N E • A P R I L 2 6, I 9 8 8 134 ----'.--- .... -- _._--.,.-~"fi • 1,4(;) Relative TImes lerilL.rl'orrnar,ce TImes (H.yes V-5eries Smanmodem 9fiOO _j 00) Character Turnaround 'I.1ixed Xmodem P C M A G A Z 1 N E • A P R I L 2 6. 1 9 8 8 135 • • HIGH-SPEED MODEMS fiTIl Performance Tests: noise-Ievels. Since lhe TAS 1010 providas Modems with higher graph Unes have line impairments in onJy one direction, we higher throughput ove< a range of noise luIid High-Speed Modems connecled two TAS 1010s ba<;k-Io-back lo levels.liigher throughput in this case provida a bad Jine in both directions. represents better immunity to telephone or lhe olher h1gh-speed-modem Tasl results are presented on graphs 01 line noise. Some modems were unable to F lhroughput lests, we set lhe iAS 1010 lhroughput in characters per second (cps) complele ali lhe lests because lhey channel simulators to emulais a pertect versus decibelslrelative noisa. Une quality stopped transmhting accurately ar stopped telephone fine-that is. wit.h no line naisa doereases from left to right on lhe graph. transmitting attogether ai certain noise whatsoever. For..the Slgnaf..to.Nolse leveIs. Ratlo testo however, we measured each modern's performance on noisy lines. Ganclal! Access Serias V.32 PCJlace 24196 (asymmetrical.protocoI) For lh!s les!, we programmed lhe 1200 I channel simulators for a worst-case kmg· 1~1~------i distance fine and measured the modems' 800 Ihroughput at varying'"decibels/relative l r _ ~ ;;; 600 :. - ..4 •••• .... 4ft. . '5. .'10":'.... ''f':'l.~, ~ -' '" "'" 0'0., ' ..' ..... ,' h ~'...... Slgnal-to-Nolse Ratlo } •, 200.... ", ...... """''[-".,. ,"o .. :10 (~ givanln chasacl8fs per secord for each leY8I cf dedbelslntlaiive noise) -31 -29 .Z1 ·25 ·23 '2,1 ·19 Hayas v-Serles Smartmoêlem 9600 Raca~Vadlc 9600VP .200 .200 , '1000 ~.r -' ' •• 1200 ' 1 1~ • il 600aoo 1·- ,,"'--... - .,.=zt-' çJil;f'l! "§aoo ,i"" i= ~. -, -.r,GAWS4 ~400 g400 ~g .- .-I"" ~ ""31C:';'4:id. '~~ ~ , 8 200 2""" ~ .1 -1' 'f"._] ~,.~·i- I f' o !'~ ' F ' r }'·.J~7'=::j1' -33 ·-31 .,29..z7 ·25 ·23 ·21 ·19 ·31 -2$ ~Z1 -25 ·23., -21 - 19 UDS V.32 121lO '000 !"800 1=o ~2SI -Z1 ~25 -23 ~ ·19 P C M A G A Z I N E • A P R I L 2 6. I 9 8 8 136 • can be difficult \O seI up a modem Ihal onJy uses software commands ir you have to change lhe wa)' il comes OUl of lhe box. The DlP swilches can be overridden by software commands if differenl programs require different senings. 1t .s nice to have '11111111111 a choice. It would also be nice lo have a r-""\--'M knob on lhe volume conrrol 50 you don 'l need a screwdriverto adjust it. Surprisingly, lhe Microcom was lhe onll' modem we leSled lhal allowed errors. to pass in lhe noise torture tests. While mosl modems juS! dropped lhe line when lhe noise levei gOl 100 high. lhe Microcom aClUall y introduced errors imo lhe dala. The Microcom AX/9624c is a fair per former overal!. bUI ilS poor performance on noise teSlS. confusing documemaLion, and problems in hanging up make il less Ihan slellar.-Howard Marks RACAL-VADIC Racal-Vadie 9600VP Racal-Vadic has a long and well-deserved reputal ion for making rugged and innova uve modems. Its 3434 was lhe fllSl full-du plex 1.200-bit-per-second modem avail ahle for dial-up applications. It even beal The Raca/-Vadie 9600VP has a Jow-profile cabiner anti a slanred. easy.lo.read displa)' wilh LEDs AT & T' s Sell 212 lO markel by several in its answer bUlIons. Cooling vcnts are Jocaled loward lhe bacJ.. . months. BUI it wasn 'l c1ear until lower coS!2 12-compatible models becarne avail able Ihal lhe 212 "slandard" would really asymmeoical modem. RacaI-Vadic decid eITOr cDrrectiDn . The resuh is a rnooified become established . ed 10 have ilS $995 9600VP drop imo version of lhe public domain MNP CIass 3 Once agai n. with no clear slandard in 1,2oo-bps mode when lhere was data lo be prolocol lhal resends only Ihose blocks Ihal place, Racal -Vadic has taken an inoova sem in bolh directions. Racal-Vadic uses have data errors. Racal-Vadic's resulting li ve approach lO solving lhe problem aI lhe widely available Rockwell V.29 mo " Supersel MNP" prolocol should give hand. Ralher lhan build a ping-pong or dem module in lhe le ss nDise-sensiti ve bener throu ghpul on noi sy Jine s. since 253-millisecond standard mode. 11 man MNP also resends ali lhe blocks sem after ages lo do so wilhoul making lhe modem lhe dala block lhat contains lhe error_ 1 11~ unusable in imeractive applicatiDns. Ra· cal-Vadic caIl, Ihi s unique mode of opera NO COMPRESSION Unfonunalely, ~ FA CT F I L E tion " Dynamic Duplex. " Racal-Vadie didn 'l include dala compres RacaJ· Vadie 9600VP In real-world use, lhe 9600VP fe lt likea sion. This pUIS lhe 9600VP aI a disadvan Racal·Vaclic ., l,2oo-bps modem when used in inlerac tage when compared with lhe Olher pseu 1525 McCarthy Blvd. tive applicatioos. While Ihis waso 'l ncarl)' do-full-duplex modems. 9600VP users Mjlpitas. CA 95035 as nice as using one of lhe true V.32 mo can partially make up forlhis by eompress (408)432-8008 Lisll'rice: 5995 dems, it was betler than some Df Lhe slDwer ing files wilh readily available utilities like Re PC MAGAZINE . APRIL2 6. 19 88 137 • • HIGH -SPEED MODEMS lhe modem wilJ dial number 13 if lhere is no answer to a Ca11 10 number 2. Vou can'l mix commands from lhe two command seiS, 50 flags-like clear-I<>-Send (crS) handling ar aul<>-answer On----sel in Vadie mode remain sei in A T mode. You can even enter Vadie mode commands from lhe len-bullon froOl panel. This could come in handy for people wilh dumb ler minals. bUI PC software usually makes lhese fealures superfluous. The 9600VP's 10w-profiJe cabine.1 in- . cludes LEDs for transmined and received dala, error correction, high speed. cJear 10 send (crS). data sei ready (DSR), data ler minal ready (DTR), ring indicator, and carrier detecl in addition la lhe from-panel swilches. The LED in lhe answer bunon displays lhe modernos aUlo-answer status. Racal-Vadic has also reaJiz.ed lhal compul er people use power smps, SO ilS designers pUI a cord on bolh sides of lhe line trans former so it would take up one ouue!. Even lhough lhe 9600VP has been on lhe markel for some time, Racal-Vadie sem us an early produetion model for teSI 10 ing. Currem production units. unlike Qllr Sricking a srraighrfonvord designo Telebü" s TraiLBlour Plus Iras a block pebbled casing wilh sample, may nol have lhe wine-wrap wine only DlI LED display to olle side of lhe from pallel_ and chips wilh pins in lhe air. However, lhe 9600VP's manual showed no rough SpolS. A rarily in modem manuals, lhe some lUmaround problem. lhe screen falling one or rwo characlers be 9600VP's is lechnically complele and During characler-tumaround leslS, lhe hind your Iyping, Ihen calching up in rcadable. II even incJudes a few words on modem managed 122 milliseconds-mak bursls. This lag, however, is nOI slo", _ using lhe 9600VP wilh PCs and popular ing it second onJy to lhe Hayes Smartmo enough lo be a problem. PC communications packages incJuding dem arnong non-V.32 modems. In aelual The modem's file-transfer time is still Crosslalk, Carbon Copy, and Close-Up . use, if you type fasl enough. you can see nOleworthy. Part oflhe "Plus," in facl. is Even wilh Dynamic Duplex and Super a newly added data-compression scheme. Sei MNP, lhe 9600VP is only a fair per which Telebit c1aims can compress lext former when compared wilh lhe resl of lhis files as much as 1.6 10 I. group. Perhaps lhe promised 9600PA wilh On PC Labs leslS over a cJean line, lhe 2,400-bps Dynamic Duplex and data com FACT FILE TrailBlazer Plus managed lhe faslesl time pression will be bener.- Howard Marks TraUBIaur.P.lus of any modem ICSled. BUI while ilS 1,538- Telebit Corp. characler-per-second speed is only slightly 1345 ShorebUd Way fasler lhan lhalOf Ven-Te!' s Palhfinder. be TELEBIT CORP_ .Mountain View, CA 94o.·13-J329 aware thal Ven-Tel uses lhe same protocol (4 15) 969-3800 as lhe TrailBlazer (having licensed il from TrailBlazer Plus 1..ist Pri P C M A G A Z I N E • A P R I L 2 6. I 9 8 8 138 • • HlGH·SPEED MODEMS lhe TrailBlazer has special modes for NOT FULLY HAYES-COMPATIBLE Xmodem and Ymodem. and for Kermil Be aware lhal lhe TrailBlazer is nol ful! y ! ! j !oi transfe". When lhe modems are sei for lhe Hayes-compalible. Like lhe Hayes Smart appropriale prolOCOI. each modem sends modem 9600. it stores ali seltings in non bji~ F I L E ilS local computer lhe acknowledgmenlS volatile memory. BUI ilS extended com· UDSV.32 required by lhe soflware before going 10 mands have little In common with lhose af UmvasaJ o.u. Systems lhe neXI packel. lhe currenl Hayes Smartrnodems: instead. 5000 Bradforo Or. lhe TrailBlazeruses a SUpe,,"1 oflhe origi· Hurusville. AL 35805 (205) 72 I -8000 nal Hayes command~ . A useful discusslOn li5t Price: St.595 of lhe differences belween lhe TrdÍlBlazer R belween modem and computer-bul lhey seconds--enough thal you may need 10 ad· What ' ~ more. Lhe rwo-tone gTay and I use lheir own proprietary prolocol betwccn just your communjcaLions program so lhar while colors match your PCor AT exac modems. il won'l time-out. giving lhe look of a shrunk-down. dis For lhe prolocol support lO work, bolh In addilion IQ using ils high-speed cousin. Pul il on top of your PC. and modems musl be sei properly before eSlab mode, the TrailBlazer can communicale UDS V.32 willlook righl aI home. lishing communications. We had to ignore wilh olher modems at 300 bps using Bel! More imponant. Lhe modern's Clair lhis fealure because in PC Labs leslS lhere 103 protocol. 1.,200 bps with Bell212 and a place in lhe PC markel is hardly a sup' was no way 10 SIOp lhe file transfe" and re V.22 prolocol. and 2,400 bps wilh V.22 cial one. Of ali lhe V.32 modems revie set lhe modems. bi s. At low speeds (2,400 bps and below), here. lhe UDS modem is lhe only one Alas. lhe TrailBlazer a1so does nOI hold lhe TrailBlazer offe" suppol1 for MNP makes a serious 311ernpt aI Hayes com) up over noisy lines. While lhe modem Classes I through 3. bility. mainlained respectable speeds in ali ca""s Selling for $ 1,345, lhe TrailBlazer of where il worked, il gave up complelely fers an acceplable mix of features and per SOME INCOMPATIBILITY E when faced with an avcrage amount af formance for lhe price. BUI based on PC models provided for review had some noise 00 a worse-than-average line. More Labs noise teslS, it's a hard one to recom nor incompalibilities wilh lhe H: impol1anlly, lhese were conditions under mend over lhe slighlly slower Ven-Tel Smartmodems-primarily in default which ali bUI aoe other modem continued Pathfinder. Under mOSI conditions, the tings lhal differed from Hayes's. Ac< 10 work. Telebil TrailBlazer should perform well . ing 10 UDS, Ihese problems have This result was surprising, since the On marginal lines, it may run imo prob fi xed, and lhe ve"ion being shipped a TrnilBlazer monitors hoc conditions and lems.-M. David Stone writing is fully compatible with lhe S, adjuslS transmission speed lO accommo modem 2400. (lf you received lhe date changes in conditions. The fall ve"ion, you can gel a free upgrade.) backlfall -forward scheme is supposed lO ~VERSALDATASYSTEMS The claim of fuI! compatibilily adjusI speed in increments of 100 bils per UDSV.32 strictly OlJe, bUI where Ihere are d second aI a time. When V.32 modems parade imo lhe PC ences, lhey make good sense. The S, Interestingly enough, Ven-Tel's Palh· marketplace in a bi g way, lhe UDS V.32 is modem's AT B command. for inse finder-Ihe TrailBlazers li censed cou likely to be leading lhe bandoThe leasl ex chooses belween V.22 protocol and sin-maintained ilS speed far bener on lhe pensive V.32 modem reviewed here by 212 protocol ai 1,200 bits per second. noisy lines. far, lhis $1 ,595 unit approaches lhe price isn'l an issue for lhe UDS modem, , P C M A G A Z I N E • A P R I L 2 6. I 9 8 8 140 • • IDGH-SPEED MODEMS explaining how to use lhe modem, it gives almast no background information. A typical example shows the message "Far end echo Level=- P C M A G A Z I N E • A P R I L 2 6. I 9 8 8 143 '. H1GH-SPEED MODEMS fi]í;lE D I T O R ' S , .C H O I C E .'UDSV.32 lfy ou have no urgem need ofa high . speedmodem, )'Ou moy 1I'II/l1 1() waiJ aJew monlhs.lt's Jikelyyou'llfind . '7IeWer produclS on the 11IlJTiIel, mui )'Ou may be.abJe 10 bener delermine which one ~ inJernaIioruU stan .dards seem 10 bef orming around. Among lhe high·speed nu> P C M A G A Z 1 N E • A P R 1 L 2 6, I 9 8 8 144 • • lllGH-SPEED MODEMS tions, and Ihey are able lO aUlomatically VEN-TELINC. downshift fm;1 lo 7,200, Ihen 4,800 if ij l \.i needed. If lhe Iinc improves, lhe modems Pathfinder 18K aUlomatically shift up lO lhe nexl higher Ven·Tel's Pathfmder 18K was one of lhe ~ FA CT F I L E speed.ln our teslS , lhe modem dropped lhe fastesl modems in our tesl group--espe· Pathfinder 18K conneclion enLireiy. cially when sending less-compressible V..,·Tcllnc. The Courier HST uses OIP switches to data pattems like archive (.ARC) files. 2t21 Zanker Rd. conrrol some af its settings--the single The Palhfinder uses lhe unique multicar· SanJose, CA 9513J-2JTI bank of ten sw ilches being easily reachable rier PEP (Packetized Ensemble Protocol) (408) 4Jó.7404 lisI Pri P C M A G A Z 1 N E • A P R I L 2 6. I 9 8 8 146 SINCE 1983, RACORE HAS PROVIDED ... 40,000 • illCH-SPEED MODEMS PCjr's gotiation process is accompanied by a ca With PC Power cophony of beeps and squacks since lhe speaker disconnec15 from lhe phone line aI lhe end of lhe processo One SysOp lhal • One unique feature uses lhe TrailBlazer calls iI a "bug zap of the Pathfinder is per" since lhe negotiaLion tones sound just like one. Calling a Palhfinder wilh a low ability to imitate speed modem takes an especiaHy long its time because lhe Palhfinder nies 10 make a protocols nonnally used high-speed connection before ancmpting a low-specd conneclIon. ]f you will have with communications bolh high- and low-specd callers. make sure lhe low-speed callers seI up lhe" sys software while still tems 10 handle lhe long connecl Lime. ar they ma)' glve up juS! a"\ the canneclion is using its OWD scheme_ Drive Two Plus Gllles your IBM being made. PCjr lhe performance capabilities Df a PC by adding a second dnve plus enhancements. Ttle uml Includes a COMFORTABLE F1T The Palhfinder parallet porto a second dlsk dnvB. clock is significantly ,mal ler lhan lhe TmilBlaz off lhe prolocol overhead and sends ti calendar with banery back-up, adchtlonal er. Il< aluminum case firs comfortably un data across lhe phone Itne usmg. ilS own e power 10 lhe slde bus ano a memory der a standard desk lelephone. 115 fronl expansion slol. Your PCjr can now run mr-correcnon scheme. PC sohware. panel contains severa] LEDs-including AI lhe olher end. the olher model Drive Two Plus wlth DMA some bicolor LEDs lhal can glow either builds Xmodem packers and "'nds lhem , red or green. These bicolor LEDs are cov iLS compUlcr. This method ensures con $299.00 $349.00 ered wilh clear windows lhat from lhe puter-to-computer error chccking-nl wrong angle make them appear In even j usl for lhe modem-Io-modem link. li ai, Expand to 640K Give your PCjr when they are noL Ven-Tel has shown avoids lhe additional overheCId of runniI lhe mBmory il needs with RACORE's greal wisdom in supplying lhe Pathfinder lwO crror-correcUon prolocols ai th e" san expansion boarns. This plug-!n board tits wilh a u-ansfonner lhal ha< cables for bolh time. This speed improvement can be sil InlO lhe Onve Two Plus ar lhe 20MB lhe modem and AC sides of irs connec nificant; you'lI fi nd lhe melhod espcciali Bxpansion units and providas up to 640K of memory in 256K increments. tions. PC users rarely have room on their handy if you 're using lhe Kennil 8lh-l power sllips for lhose huge combination quoting feature for communications wi Memory Expsnsion Bosrds plug-u-ansfonners and would willingly pay mainframe computers. 256K 512K an additional $2 for a u-ansfonner wilh a The Pathfinder supporls lhe bas $119.00 $149.00 cardo Hayes A T command seL bUI many of tl Besides lhe PEP high-specd prolocol, extended A T &T commands an: nol su Keyboards Choose from Ihree lhe Palhfinder supports lhe 300-bps Bell poned. Those functions are supplied , different keyboard packages complete 103 and lhe I ,200-bps Bell 212, as well as additional S registers. Ven-Tel is clero with adapIer cab6es fOI' your PCJr. lhe CCIIT V .22 and lhe CClIT 2 ,400- targeting lhe PC markel wilh lhis mode, PC Style $99.00 bps V.22 bis protocols for lower-specd and lhe readable manual includes dire communications. MNP Class 4 is supplied tions on using lhe Pathfinder wilh popu) ATStyle $119.00 for communications in any of lhe low communications software such as ero! specd protocols. Ia1kXVI. 5151 Style $139 .00 One unique feature of lhe Palhfmder The Palhfinder is a quality product a (and Telebil 's TraiIBlazer Plus) is i15 abili should be considered for any poinl-! CALL TOLL FREE . c:!E:j ty to imitale prolocols nonnally used wilh paim communicatians need. On the oU 1-800-325-1833 communications software while stiU using hand, il seems unlikely lhal Telebil te< 1-800-521-6366 (in Cali!. ) its own. more-efficient error-coITeclion nology will become lhe indusuy standru BBS: (801) 363-8720 scheme between lhe two modems. When so users looking for long-tenn public hif using lhis protocol, your PC will send data speed communications might want to pô RACORE Computer Products Inc, 170 Knowles Drive, lO lhe Pathfmder using lhe Xmodem, Ker it by.- Howard Marks Los Gatos, Ca. 95030 mil, or UUCP (UNlX-to-UNlX Commu (408)374·8290 PrIClll5 SUIlfeC' 10 CfW>CIe WIIhOuI no\IOIl nications Prolocol) prolocol. Then lhe mo Howard M arks is an independem sysle RACORE. o...... T-o ~"' l egnWeCI ~ ol RACORE COm!:xI\8t ~ Ire dem will respond to lhe computer as if iI consuflanJ anti free-lance writer based IBM. PC. XT. AT.~ . .. I"'I1'$*ed ~ oll8M Co,Ionncn were the other end of lhe communicatians NewJersey. M. David Stone is a Conlr linle At lhe saroe time, lhe modem sllips ming editor oJpc Magazine, ORCLE 167 ON READER SERVICE CARO PC MAGAZINE. APRIL26.1988 148