I
DTR(DataTerminalReady)protocoldoesthe samethingslightlydiffer-
ently.The,printersendsa continuoushigh-voltagesignaloverthecableas
long as it can accept data, but drops the voltageto say “whoa”to the
computer.
Conversely,it’sthecomputerthatholdsthereinswiththeETX/ACK(End-
of-text/Acknowledge)protocol.Thecomputersendsan ETXcontrolcode
aftereachstringofdata,andwhentheprinterfinallygetsthatcodeitsends
anACKcodebackto thecomputer,askingformore.Thisprotocolis less
used by modem computersbecauseit doesn’thold back data when the
printer’smemorygetsswamped,
Look in your computer’soperationsmanual,in the sectiondealingwith
communicationsprotocols,to sce whichis bestfor yoursystem.Youcan
sticktotheprinter’sdefaultsif yourcomputerusesneithertheDTRnorthe
ETX/ACKprotocol,butdoesuse XON/XOFF.
If you wantto enableDTRor ETX/ACK,or disableXON/XOFF,you’ll
have to set thoseparametervaluesaccordingly.Turningon onc of these
protocolsautomaticallyflipsoff theothers.
Checking your connections
Yourcomputerandprintermayhavetroublecommunicatingwhenyoufirst
introducethcmtoeachother.Thequickwayto findoutif yoursettingsand
printercableare workingistosendyourprinteraprintoutfromyourscreen
(CHW-P withMS-DOS).
Whenthat’sdoneyouwillalsohavetopresstheprintbuttonon theprinter,
whichm’akestheprinteradvancetoanewsheet.Nolaserprinterprintsand
ejectsapageuntilit’stoldtofeedaform,oruntilithasreceivedallthelines
thepagecanhold.
If yourStar LaserPrinter8 doesn’tprint what’son the computerscreen,
recheck your connectionsand interface settings. With an applications
programlikeLotus1–2–3orMicrosoftWord,youuscapnntersctuproutine
to match yourcomputerwith yourprinter’soperatingcharactcnstics.So
double-checkyoursoftwaresettings;yourcomputer’soutput,forcxarnple,
mightnotbegoingto theproperport.
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