Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!husc6!rice!sun-spots-request
From: auspex!guy@uunet.uu.net (Guy Harris)
Newsgroups: comp.sys.sun
Subject: Re: hp plotter
Keywords: Software
Message-ID: <304@brazos.Rice.edu>
Date: 22 Jul 89 20:48:30 GMT
Sender: news@rice.edu
Organization: Sun-Spots
Lines: 16
Approved: Sun-Spots@rice.edu
X-Sun-Spots-Digest: Volume 8, Issue 79, message 4 of 15

>I think your problem may be with flow control - the first buffer gets sent
>properly and the HP then tries to use RTS/CST to tell the sun to wait a
>bit.  The sun ignores this and then ... The way out is to tell the HP to
>use XON/XOFF flow control (and also apply YAPT 5.??? if your running SunOs
>4.0.1).

If you're running SunOS 4.x, you might just try telling the Sun *not* to
ignore RTS/CTS flow control, by using the "ms" capability in "printcap"
and specifying "crtscts" mode.  (Note: it's unidirectional RTS/CTS flow
control - i.e., the Sun can't control flow of data *into* it - but for a
printer or plotter, that should be sufficient.  Bi-directional flow
control, unlike unidirectional flow control, requires software changes -
it can't be done just by the hardware, as unidirectional flow control can.
Note also that the ALM - i.e., the Systech MTI board, as opposed to the
Sun-built ALM-2 - *always* does unidirectional RTS/CTS flow control,
although you can tie CTS high and disable it.)