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From: jhc@mtune.ATT.COM (Jonathan Clark)
Newsgroups: comp.sys.att,comp.unix.questions
Subject: Re: UUCP dialout, uugetty fighting...
Message-ID: <1169@mtune.ATT.COM>
Date: Sat, 5-Sep-87 23:39:10 EDT
Article-I.D.: mtune.1169
Posted: Sat Sep  5 23:39:10 1987
Date-Received: Sun, 6-Sep-87 09:53:23 EDT
References: <2896@psuvax1.psu.edu> <1463@chinet.UUCP> <18171@amdcad.AMD.COM> <1187@dasys1.UUCP> <1485@chinet.UUCP>
Reply-To: jhc@mtune.UUCP (Jonathan Clark)
Organization: AT&T ISL Middletown NJ USA
Lines: 31
Xref: mnetor comp.sys.att:1167 comp.unix.questions:3916

In article <1485@chinet.UUCP> randy@chinet.UUCP (Randy Suess) writes:
>	I seem to be missing something with all this discussion of 
>	bi-directional modem use on 3b's.  As the above states, you have
>	to leave CD tied hi at all times for dial-out.  What happens on
>	dial-in when the carrier is inadvertently dropped?  The system
>	never sees the carrier go away, as CD is tied hi.  So, another
>	person calling in is dropped into the middle of the previous
>	callers login.  Could be real embarrassing.  Has this been 
>	discussed at all or have I just missed the answer?  

I don't think that the real answer to this has come out yet, so here goes:

The 'latest-and-greatest' HDB solves this entire problem by allowing
one to specify an optional NDELAY open() and to toggle CLOCAL and part
of the chat script on the communication line for dialout.

One would then leave DCD alone, so that an incoming call would be
answered correctly when DCD went high. On dial-out, one locks the
line, does an NDELAY open(), sets CLOCAL (uugetty wakes up at this
point, finds a lock file, says Oops! and goes to sleep), and does the
dialling, turning CLOCAL off at some appropriate point, like when DCD
has come up.

I don't know who thought of this, but massive kudos to them.
And no I don't know how anyone gets hold of this version, it's
difficult enough for me! It's bound to be in a release sooner or later.
-- 
Jonathan Clark
[NAC,attmail]!mtune!jhc

An Englishman never enjoys himself except for some noble purpose.