Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!tut.cis.ohio-state.edu!ucbvax!agate!shelby!neon!kaufman
From: kaufman@Neon.Stanford.EDU (Marc T. Kaufman)
Newsgroups: comp.periphs
Subject: Re: "intelli"port problems (DTR drop)
Keywords: aha! fixed, timeout
Message-ID: <1990Jan9.170632.13160@Neon.Stanford.EDU>
Date: 9 Jan 90 17:06:32 GMT
References: <170@norsat.UUCP>
Organization: Computer Science Department, Stanford University
Lines: 17

In article <170@norsat.UUCP> dbin@norsat.UUCP (Dave Binette) writes:
-In a previous posting i grumbled about the COMPUTONE INTELLIPORT
-not disconnecting after my BBS user logged off.

-Found the problem!  (soooo simple).
-The solution then is be sure that the TTY lines are closed and
-				 *most important*
-Keep them closed long enough for the DTR drop to be sensed by the modem.
-Without the sleep(2) "getty" kicks in too fast and the modem ignores
-the very brief drop of DTR.

The standard for hangup is to drop DTR for 250ms OR until DSR (from the Modem)
drops -- whichever occurs first.  2 seconds is OK, but overkill.  Longer
sleep is to be discouraged since the phone line won't be answered while DTR
is down.

Marc Kaufman (kaufman@Neon.stanford.edu)