Subject: Re: Getting cu working
To: None <mouse@Collatz.McRCIM.McGill.EDU>
From: Gordon W. Ross <gwr@mc.com>
List: port-sun3
Date: 03/21/1996 10:57:14
> Date: Mon, 18 Mar 1996 07:03:53 -0500
> From: der Mouse <mouse@Collatz.McRCIM.McGill.EDU>

> > Things like this keep happenning:
> 
> > % stty -f /dev/ttya speed
> > 9600
> > % stty -f /dev/ttya 2400
> > % stty -f /dev/ttya speed
> > 9600

You need something to "hold the device open" if you want to be able
to set the speed and have it persist.  This is a farily common thing
on POSIX-ish systems (the device is reset on first open).

Try this:
	sleep 999999 </dev/ttya &
	stty -f /dev/ttya 2400
	...

> > % cat >/dev/ttya
> > Now I type random garbage^D
> 
> > results in dtr on the modem going on, but the ^D will not stop the
> > input; ^\ causes csh to dump core, stopping it.
> 
> Sounds as though the shell's open() call on /dev/ttya is blocked,
> probably blocked waiting for carrier.  Is the line set -clocal by any
> chance?

There was a bug in the "wait for carrier" code in the sun3 zs driver
which could cause failure to notice carrier turning on.

Also, make sure you either have CD wired to something (i.e. DTR)
or mark the line as "local" in /etc/ttys (or set -clocal).

Gordon