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From: julian@mailhub.tfs.com (Julian Elischer)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: How do I reset modem/unlock ttyd0?
Date: 23 Nov 1995 06:03:15 GMT
Organization: TRW Financial Systems, Oakland, CA
Lines: 66
Message-ID: <4912r3$9ag@times.tfs.com>
References: <48sonv$848@owl.und.ac.za>
NNTP-Posting-Host: mailhub.tfs.com
In article <48sonv$848@owl.und.ac.za>,
Ewan McPhail <chops@kestrel.ugrd.und.ac.za> wrote:
:Hi All,
:
firstly, you don't say which version of freebsd.. this has changed a little
over time but I'll assume it's pretty recent..
:This is a semi-urgent hassle, so I'd truly appreciate anyone
:who could assist me...
:
:I have problems on my machine with the modem "hanging" - ie it
:remains "off hook" when someone drops carrier.
is this dialing in or out?
you don't say..
I presume In..
in the default configuration, the login should get a SIGHUP when the
DCD line is dropped and the session should end..
you do have the modem set up with AT&C1
(drop DCD on carrier loss) don't you?
:
:What I want to know in the interim is how do I unlock the
:device (ttyd0) - I know FreeBSD created "locking" files
:in /dev so nobody else can access the modem - as root, I get
:"device in use" when trying to output to it.
not in /dev..
cu and tip and friends make file somewhere in /var.... (/var/locks?)
:
:Will something like "echo +++ath0^M >> /dev/ttyd0" do what I
:presume it will? And if not, how do I reset the modem
:without rebooting (a reboot does, however, solve the hassle)??
yes because that will drop DTR which will force the modem get it's
act together.
:
:Much appreciated anyone...and if you know what causes the
:hassle in the first place, I will be eternally gratefull :)
rules to be followed when using modems...
with ALMOST NO EXCEPTIONS
use REAL DCD signals and make sure pin 8 is PROPERLY CONNECTED
(assuming 25 pin connector)
used READ DTR (pin 20) MAKE SURE IT's connected..
make sure all switches/jumpers on the modem turn these signals ON
(not STUCK ON, but REALLY ON i.e. they indicate real status.
use AT&C1 and AT&D2 to ensure the modem is doing the right thing too.
(and save the setup)
AT&D3 is recommended for those that support it.. (reset modem on hangup)
All DIAL IN services (e.g login, uucp etc) should use the ttyd devices..
ALL OUTGOING services should use cuaa devices..
If you do this correctly and don't fiddle with the setups of the ports
then it should all just work......
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