Xref: utzoo comp.sys.dec:1534 comp.unix.ultrix:1250
Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!usc!csun!fedeva!bill
From: bill@fedeva.UUCP (Bill Daniels)
Newsgroups: comp.sys.dec,comp.unix.ultrix
Subject: How does lpr know printer is offline?
Keywords: HELP, lpr going bananas!
Message-ID: <463@fedeva.UUCP>
Date: 21 Jul 89 14:39:26 GMT
Organization: Federal Express Corp., Memphis, TN
Lines: 21

We have a Printronix P300 serial printer connected to an Ultrix MicroVAX
3800 via a CXY08 8-line RS232 controller.  Which of the RS232 signals
is monitored by the lpr print spooler to recognize that the printer is
off-line?  The printer can be configured to drop either CTS or DTR.
The printer can also send an XOFF (dc1/^S) but this seems to be ineffective
if the spooler is not in active communications with the printer; I guess
nothing has the port open for read at the time in order to pick up the
software flow control character.

We are really trying to avoid a situation in which the printer is placed
offline while the spooler is inactive and a print job queued while the printer
is still offline.  In this case the spooler goes merrily about its way of 
dumping a bunch of stuff to the printer which isn't expecting it, doesn't
know that it has started, and consequently loses the job.

We also have available DECserver 200/MC ports across LAT if that will help
with a solution.
-- 
bill daniels
federal express, memphis, tn
{hplabs!csun,mit-eddie!premise}!fedeva!wrd3156