*BSD News Article 58031


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Newsgroups: comp.unix.bsd.freebsd.misc
Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!nntp.coast.net!news.sprintlink.net!dfw.nkn.net!rowdy.lonestar.org!nemesis!uhclem
From: uhclem@nemesis.lonestar.org (Frank Durda IV)
Subject: Re: Modem Problem, LEDs goes berzerk!
X-Newsreader: Tin 1.1 PL5
Organization: The Big Blue Box
Message-ID: <DK1s50.53o@nemesis.lonestar.org>
References: <4b3m50$mo@sia.sics.se>
Date: Sat, 23 Dec 1995 16:22:12 GMT
Lines: 51

[0]Lars Nilsander (lasse@mont.sics.se) wrote:
[0]Having problems with a modem under FreeBSD, directly after I get the 
[0]login prompt all LEDs on the modems starts blinking (login/getty problem?). 
[0]Are there any tools for FreeBSD with which I can see who's messing 
[0]with /dev/cuaa1 and /dev/ttyd1 (lsof, ofiles compile?)


1.	Make sure you have issued an ATE0 to the modem.  This prevents it
ATE0	from echoing characters it receives from the CPU back.  If you don't
	do this, you can get into what we used to call a "getty war", where
	the computer would send out the login banner, the modem would echo
	it along with possibly the phrase "ERROR", then the computer would
	respond "Password:" and the modem would echo that and the computer
	would say "Login incorrect/ Login:" and the modem would echo that,
	and on and on.

2.	You also need to set AT&D3 or if you don't have that &D2.  This
AT&D3	tells the modem to hang up when DTR is dropped, and for &D3 to reset
	all settings to the reset state when DTR is dropped.  This prevents
	settings for one outgoing call affecting the subsequent incoming or
	outgoing calls.

3.	You might also need to make sure you have flow control signals
AT???	enabled if available.  These commands vary wildly by modem type,
	so you must check your manual.

4.	You have requested the modem return real carrier information
AT&C1	(AT&C1, or on a few modems &C2 might be better).
	This ensures that the user will be logged-out when the carrier
	drops, rather than the session still being present when the next
	party calls in and gets into someone elses' account.

5.	You should also disable reporting of status, at least during
ATQ2	incoming calls.  Not all modems support the distinction of incoming
	vs outgoing, so you might have to disable all messages.  You don't
	want the "CONNECT nnnn" message sent to the host when someone is
	calling in as it might be taken to be the login name by the system.
	This command varies by modem brand, but it usually is ATQ2 to disable
	reporting on incoming calls and ATQ1 to disable all reporting.
	For ideal UNIX modem operation, no messages should come from the
	modem at all except during outgoing calls when there is a chat
	script or some other mechanism to deal with them.

6.	All of the above settings you select MUST be stored in the modem
AT&W	by using AT&W so that they will be in effect at all times. 

Frank Durda IV <uhclem@nemesis.lonestar.org>|"The Knights who say "LETNi"
or uhclem%nemesis@fw.ast.com (Fastest Route)| demand...  A SEGMENT REGISTER!!!"
...letni!rwsys!nemesis!uhclem               |"A what?"
...decvax!fw.ast.com!nemesis!uhclem         |"LETNi! LETNi! LETNi!"  - 1983