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From: andrew@alberta.UUCP (Andrew Folkins)
Newsgroups: net.micro.pc
Subject: Does DOS listen to LaserJets?
Message-ID: <596@alberta.UUCP>
Date: Thu, 25-Jul-85 19:46:19 EDT
Article-I.D.: alberta.596
Posted: Thu Jul 25 19:46:19 1985
Date-Received: Thu, 1-Aug-85 21:51:25 EDT
Distribution: net
Organization: U. of Alberta, Edmonton, AB
Lines: 24

Does anybody out there have an HP Laserjet printer hooked up to their
PC/XT/AT?  If so, does DOS notice when the printer hangs? The specifics :

IBM AT running DOS 3.0
HP Laserjet printer attached to COM1 
In AUTOEXEC.BAT : MODE com1:9600,N,8,1,P    (as given in printer manual) 
                  MODE lpt1: = com1:   

When ever I try to print a file more than about 3K the Laserjet overflows, 
and DOS keeps on sending data. Experimentation has revealed that communication 
over the com port is done with XON/XOFF protocol, with the Laserjet normally 
sending an XON about once a second, and an XOFF when it dies. To get around 
the problem, I wrote a short communications program which reads data from the
file and sends it to the printer over the com port (same parameters as above),
and pauses when it receives the XOFF (usually when the printer runs out of
paper).

I can't believe that the printer and DOS are incompatible, but aside from
slowing the PRINT command down to a crawl by increasing the timeslice size, 
or writing my own print routine, there doesn't seem to be any way around this.
Any suggestions?
-- 
Andrew Folkins               YABS : If you think education is expensive, 
ihnp4!alberta!andrew                consider the price of ignorance.