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Date: Mon, 17 Jun 1996 09:35:42 -0500 (CDT)
From: David Kelly <dkelly@HiWAAY.net>
Message-Id: <199606171435.JAA12507@fly.HiWAAY.net>
To: chrisl@bbs.justcompute.com, questions@FreeBSD.ORG
Subject: Re:  Help with serial terms and modems
Sender: owner-questions@FreeBSD.ORG
X-Loop: FreeBSD.org
Precedence: bulk

>Ok Im stumped... I am trying to enable ttyd0 on my system for a connection
>through a NULL MODEM cable. I have tried, tried and tried again. I have
>edited my "ttys" file for ttyd0 "/usr/libexec/getty std.9600" unknown on
>secure. But I fail to get a connect. I have tried 3 different null modem
>cables.. Im about ready to pulll my hair out! Can you offer any help? Oh
>yes my serial ports do exist and are recognized as 16550 Uarts. I just
>don't know what else to try..

Start with a "kill -HUP 1" to tell init to re-read /etc/ttys. Then you
might try "ps -aux | grep getty" to verify the getty has been started on
your serial port.

As for playing with serial ports and cables and stuff, there is a simple
"tester" with (7) bicolor LED's available at Radio Shack for under $15 (and
elsewhere for less) that I find essential. Not only can you tell at a
glance what state your serial lines are in, you can tell the difference
between DCE and DTE equipment. Simply plug the tester into a serial port
and note if RxD or TxD lights. Unplug it from your serial port and plug it
into the cable. If none of the LED's light that were lit before, then you
have reason to suspect that you have the correct cable.

This little tester is also great for watching CTS/RTS and CD/DTR pairs on
modems.