A/UX and carrier detect

[Andy Peterman]

In article <1990Dec14.175043.291 at skbat.csc.ti.com> dittman at skbat.csc.ti.com (Eric Dittman) writes:
>I took a look through the manuals and didn't find this documented, so here's
>a quick question:
>
>What does A/UX 2.0 want in terms of hardware handshaking on the built-in
>serial port?
>
>I have wired my cable with HSKi and HSKo going to RTS/CTS.  There's also
>a GPi available.  Will A/UX allow use of GPi for carrier detect from the
>modem (including dropping the session if carrier is lost)?  As it now
>stands if I log in and then lose carrier calling back puts me right back
>were I was (without the login: prompt) which I don't want.  I want the
>system to require another login.

I got it to work by connecting HSKi to the DCD of the modem (pin 8).  At
the time, I was not aware of the GPI pin which isn't documented anywhere
except in the Mac Hardware Reference Manual.  I know in the past, on
Macs which didn't support the GPI pin, the HSKi was sort of used for
this purpose.

To get A/UX to respond to the loss of carrier, make sure your initab line 
looks something like:

du:2a:respawn:/etc/getty tty0 mo_2400

or whatever speed your using - the point is to use the 'mo_' form.
Then, when your modem drops DCD when the carrier drops, you will be
logged out.

However, if you're using this same port to dial out, this could cause a
problem because without an active DCD, 'cu' or 'uucico' won't work.  If
you're using a Telebit modem, you can wire this to DSR (pin 8) and set
register S53=4, which will drop the DSR line for just 200ms on loss of 
carrier, but leave it on the rest of the time.

-- 
Andy Peterman                       |   Opinions expressed
treehouse!andyp at gvgpsa.gvg.tek.com  | are definitely those of
(916) 273-4569                      |      my employer!