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From: greg@ncr-sd.UUCP (Greg Noel)
Newsgroups: net.unix-wizards,net.unix
Subject: Re: Arcane modem configuration (was Re: Modems on Ultrix)
Message-ID: <1154@ncr-sd.UUCP>
Date: Thu, 28-Aug-86 18:14:36 EDT
Article-I.D.: ncr-sd.1154
Posted: Thu Aug 28 18:14:36 1986
Date-Received: Thu, 28-Aug-86 23:46:28 EDT
References: <282@cirl.UUCP> <3030@umcp-cs.UUCP> <1149@ncr-sd.UUCP> <12834@amdcad.UUCP>
Reply-To: greg@ncr-sd.UUCP (Greg Noel)
Distribution: net
Organization: NCR Corporation, San Diego
Lines: 18
Xref: mnetor net.unix-wizards:7719 net.unix:5314

In article <1149@ncr-sd.UUCP> I write:
>The computer will provide DTR to the modem even if it is ignoring DCD.

In article <12834@amdcad.UUCP> phil@amdcad.UUCP (Phil Ngai) writes:
>In at least one version of 4.2 BSD, this is not true. When the system
>is configured to ignore modem controls, it fails to turn on DTR. .....

Humpf.  I was about to write a reply that pointed out that I probably had
a lot more experience in this than Phil did, and that I had never had a
port fail to turn on DTR, but I though I should check first.  It turns out
that he's right -- it's done on a per-driver basis, and I have never used
any hardware/driver combination that did it wrong.  Mea culpa.

I'm puzzled, though -- the RS-232 (et.seq.) protocol is \not/ that complicated,
but by the number of supposedly knowledgable people that get it just flat
wrong, there must be something subtle in it that causes confusion.
-- 
-- Greg Noel, NCR Rancho Bernardo    Greg@ncr-sd.UUCP or Greg@nosc.ARPA