Subject: Re: Modems and serial ports
To: None <richard.earnshaw@arm.com>
From: Neil Hoggarth <neil.hoggarth@physiol.ox.ac.uk>
List: port-arm32
Date: 09/17/1998 14:23:11
I think that you are getting bitten by the fact that, on Unix type
systems, open on a tty blocks if the carrier detect line isn't asserted.
Which makes it kind of difficult to send Hayes style commands to a
modem which isn't already on line ...

If you really want to mess with stuff yourself then take a look at the
"softcar" parameter to /etc/ttys ("man ttys").

I use pppd and chat and this combination does something to open the port
in a special way which avoids the problem. I can't remember whether it's
pppd or chat which contains the magic. Again, check relvent man pages
for hints.

These days I only ever use a modem for PPP, so I'm happy with things as
they stand.

Regards,

+-------------------------------------------------------------------------+
Neil Hoggarth                                 Departmental Computer Officer
<neil.hoggarth@physiol.ox.ac.uk>                   Laboratory of Physiology
http://www.physiol.ox.ac.uk/~njh/                  University of Oxford, UK
+-------------------------------------------------------------------------+