Laser Printer Applications Manual

DTR(DataTerminalReady)protocoldoesthe samethingslightlydiffer-

ently.The,printersendsa continuoushigh-voltagesignaloverthe cableas

long as it can accept data, but drops the voltage to say “whoa” to the

computer.

Conversely,it’sthecomputerthatholdsthereinswiththeETX/ACK(End-

of-text/Acknowledge)protocol.Thecomputersendsan ETXcontrolcode

aftereachstringof data,andwhentheprinterfinallygetsthatcodeit sends

an ACKcodebackto thecomputer,askingfor more.Thisprotocolis less

used by modem computersbecauseit doesn’t hold back data when the

printer’smemorygetsswamped,

Look in your computer’soperationsmanual,in the sectiondealingwith

communicationsprotocols,to sce whichis best for yoursystem.Youcan

stickto theprinter’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 workingisto sendyourprintera printoutfromyourscreen

(CHW-P with MS-DOS).

Whenthat’sdoneyouwillalsohaveto presstheprintbuttonon theprinter,

whichm’akestheprinteradvanceto a newsheet.Nolaserprinterprintsand

ejectsapageuntilit’stoldto feeda form,oruntilithasreceivedallthelines

thepagecan hold.

If your Star LaserPrinter8 doesn’tprint what’son the computerscreen,

recheck your connectionsand interface settings. With an applications

programlikeLotus1–2–3orMicrosoftWord,youuscapnntersctuproutine

to match your computerwith your printer’soperatingcharactcnstics.So

double-checkyoursoftwaresettings;yourcomputer’soutput,forcxarnple,

mightnot be goingto theproperport.