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From: duncan@vuwcomp.UUCP
Newsgroups: comp.sys.pyramid
Subject: Setting up a modem for dialin/dialout use
Message-ID: <12896@vuwcomp.UUCP>
Date: Wed, 8-Jul-87 01:27:23 EDT
Article-I.D.: vuwcomp.12896
Posted: Wed Jul  8 01:27:23 1987
Date-Received: Sat, 11-Jul-87 19:33:00 EDT
Reply-To: duncan@vuwcomp.UUCP (Duncan McEwan)
Distribution: world
Organization: Comp Sci, Victoria Univ, Wellington, New Zealand
Lines: 48

This is a question that I have seen discussed several times, but (I
don't think) directly relating to pyramids.  I would like to set up a
modem for both dialin/dialout use.

As any of you that have tried this will know, you end up with a
catch-22 situation regarding the modem control wires between the tty
port and the modem.  If you disable the modem control, and strap the
cable so the open system call succeeds, you lose the ability to detect
the remote host dropping carrier.  If you don't strap the cable, the
open will hang until dtr is seen (on bsd systems at least).

I know of several ways around this problem.

Chris Torek's (?) device driver package (which I think provides for
two special files - one for dialout, one for dialin) seems the nicest
solution, but I think you would need the source to the tty driver to
use it.  Being for standard 4.[23] it may not be all that applicable
to pyramids tty driver anyway.

A more likely alternative is to modify a program I have written by
Bill Sebok called "acucntrl".  I have looked at the code, and am
fairly certain I could modify it if I knew more about the pyramids tty
driver.  Acucntrl has specific code to handle dz's, dh's and other vax
type things, but I am not sure what has to be done to get it do work
for itp's.  If anyone has done this, or knows what has to be done,
could they please tell me.

Two other possibilities have occured to me.

One is to use the att universe tty driver somehow (system V has the
CLOCAL bit in the tty flags that would seem to do what I want).  I am
not too happy about this since the uucp runs in the ucb universe, and
I am not sure how the two would interact. 

Finally, I noticed that the itp driver has an ioctl call SETITPCARR,
which would also seem to do what I want.  But when I wrote a short
test program to try out this, the ioctl returned the "not owner" error.
This was in spite of running the program as root.

If anyone has any comments on any of these alternatives, or any info on
options I haven't considered could they let me know by email.

Thanks.

Duncan McEwan

ACSnet : duncan@vuwcomp.nz
UUCP   : "...!{alberta, ubc-vision, utai}!calgary!vuwcomp!duncan"