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From: cgordon@vpnet.chi.il.us (Crash Gordon)
Newsgroups: sci.electronics
Subject: Help wanted connecting a Tandy serial printer to an AT.
Keywords: serial port printer
Message-ID: <274834ed-58f.1sci.electronics-1@vpnet.chi.il.us>
Date: 19 Nov 90 22:55:05 GMT
References: <1990Nov15.234028.8139@watdragon.waterloo.edu>
Lines: 23


>Author: [Brian G. Hauk]
>When `copy filename com1:' is executed from the DOS command line, a single 
>line of `filename' is printed, followed by a message similar to, `error 
>writing device com1: abort, retry, ignore?'

>Choosing `retry' or `ignore' causes another line to be printed, which is 
>followed by the same message.

>My guess is that there's a `handshaking' problem.

You're right.  The printer has no buffer (or a small one), so while it's
doing a CR/LF sequence it drops its BUSY line.  This is supposed to tell the
PC to stop sending data, however when DOS sees CTS and/or DTR deasserted, it
signals a device fault.

The fix is to tell MODE to retry forever on device errors.  This is done by:
     C> MODE COM1:1200,n,8,1,P
The P (for  Printer) is the key here.

-----------------------------------------------------
Gordon S. Hlavenka            cgordon@vpnet.chi.il.us
Disclaimer:                Yeah, I said it.  So what?