Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!psuvax1!vu-vlsi!devon!paul
From: paul@devon.UUCP (Paul Sutcliffe Jr.)
Newsgroups: comp.unix.wizards,comp.unix.questions
Subject: Re: Baud-sensing 'getty'
Message-ID: <467@devon.UUCP>
Date: Tue, 22-Sep-87 14:13:46 EDT
Article-I.D.: devon.467
Posted: Tue Sep 22 14:13:46 1987
Date-Received: Fri, 25-Sep-87 00:41:38 EDT
References: <1336@dasys1.UUCP>
Reply-To: paul@devon.UUCP (Paul Sutcliffe Jr.)
Organization: Devon Computer Services, Allentown, PA
Lines: 44
Keywords: baud getty modem
Summary: check out your modem's features
Xref: mnetor comp.unix.wizards:4418 comp.unix.questions:4220

In article <1336@dasys1.UUCP> manes@dasys1.UUCP (Steve Manes) writes:
> Does anyone have, or has anyone played with writing, a getty that
> eliminates tty users having to cycle through gettydefs with a hardware
> break?  My system will soon be traveled by folks who won't have a clue
> about sending a break if they ain't at the default speed of the modem.
> They'll probably think instead that they called a very noisy line, hang
> up and never call back.

Check the owners manual to your modem.  Some newer models (mine, for
instance; a MultiTech MT224EH) allow the baud rate over the phone line
to be different from the baud rate at the RS-232 (between the modem and
the CPU).  If your modem does this, then your solution is simple.

1) Set the modem up so that it allows auto-sensing of the baud rate in
   answer mode, but always uses one baud rate (ie 2400) between it and
   the CPU.  For the MultiTech, this means entering two commands:

	AT$BA0  and  AT$SB2400

2) Create a gettydefs line that "cycles to itself".  Of course, the baud
   rate in the gettydefs line must match that of the modem.

3) Enable the port.

There is one small side-effect to this solution.  If, let's say, you have
your modem speaking at 2400 baud to the CPU, and a person logs on at 300
or 1200 baud, the modem will handle the speed conversion.  But, since
the modem is speaking at 2400 baud to the CPU, a "stty" command will show
the line as "speed 2400".  This may confuse novice users.

As an aside, I understand that the BSD getty has an "autobaud" feature
that responds to carriage-returns to sync-up to a baud rate.  This may
have been a local feature of the system I saw it on.

Oh yeah, the disclaimer:  "I have no affiliation with MultiTech except
as both a satisfied customer and an authorized dealer."

- paul

-- 
Paul Sutcliffe, Jr.

UUCP (smart):  paul@devon.UUCP
UUCP (dumb):   ...{rutgers,ihnp4,cbosgd}!bpa!vu-vlsi!devon!paul