Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!rice!sun-spots-request
From: auspex!guy@uunet.uu.net (Guy Harris)
Newsgroups: comp.sys.sun
Subject: Re: Hardware flow control under SunOS4.0 question
Keywords: Hardware
Message-ID: <1110@auspex.UUCP>
Date: 14 Mar 89 04:50:53 GMT
References: <8902201632.AA02908@MINNI.>
Sender: usenet@rice.edu
Organization: Auspex Systems, Santa Clara
Lines: 13
Approved: Sun-Spots@rice.edu
Original-Date: 3 Mar 89 09:16:25 GMT
X-Sun-Spots-Digest: Volume 7, Issue 196, message 7 of 16

>If you set up Hardware flowcontrol on the serial lines onboard (/dev/ttya
>& /dev/ttyb) youwill have no luck. I do not know if this also applies to
>other serial lines.

It should apply to ALM-2 lines, since they use the same chip (although I
don't remember whether all ALM-2s ran all the interesting RS-232 lines to
the chip or not).  I don't think it applies to the ALM/ALM-1/Systech/MTI,
since that uses a different chip; of course, that chip *always* provides
hardware flow control and, like the Zilog chip, couples it to the "shut
off the receiver when DCD drops" feature.  Systech and the SunOS Systech
driver got around that, as I remember, by tying DCD high and using some
other line as DCD; this may mean that the problem doesn't apply to the
ALM-1.