Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!uflorida!gatech!purdue!decwrl!vixie
From: vixie@decwrl.dec.com (Paul Vixie)
Newsgroups: comp.dcom.modems
Subject: Re: Modems that reset when DTR is dropped
Message-ID: <13@jove.dec.com>
Date: 11 Oct 88 07:56:34 GMT
References: <1731@ddsw1.UUCP> <721@starfish.Convergent.COM> <6592@dasys1.UUCP> <318@pvab.UUCP> <2047@udccvax1.acs.udel.EDU>
Organization: DEC Western Research Lab
Lines: 19

# Many Hayes-compatible modems will reset entirely when DTR is toggled, but
# the correct response is merely to break the connection and go into command
# mode.

Correct?  I assure you that getty(8m) does not want to talk to a Hayes modem
while in command mode.  The "correct" thing in that case is to go into E0Q1,
which will often not be the case if UUCICO just got done making an outgoing
call.  UUCP doesn't usually have a way to reinit the modem to user preferences
when a call is complete; it's darned handy if the modem will do it for you.

On a Telebit, I can get this behaviour.  On a Hayes 1200, I can get it.  On
a Hayes 2400, I can get most of it.  On other modems, I've had some serious
problems.  The Anchor Signalman XII doesn't even connect DTR to anything
internally (hah! solved that one with a reed relay that shut off the power
to the modem when DTR was down!).
-- 
Paul Vixie
Work:    vixie@decwrl.dec.com    decwrl!vixie    +1 415 853 6600
Play:    paul@vixie.sf.ca.us     vixie!paul      +1 415 864 7013