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Path: utzoo!watmath!clyde!burl!ulysses!ucbvax!ucb-vax.arpa!dual!greipa!paul
From: paul@greipa.UUCP
Newsgroups: fa.info-vax
Subject: set host/dte
Message-ID: <8509050635.AA23247@greipa.UUCP>
Date: Thu, 5-Sep-85 02:35:12 EDT
Article-I.D.: greipa.8509050635.AA23247
Posted: Thu Sep  5 02:35:12 1985
Date-Received: Sat, 7-Sep-85 13:22:33 EDT
Sender: daemon@ucbvax.ARPA
Reply-To: info-vax@ucb-vax.berkeley.edu
Organization: The ARPA Internet
Lines: 49

I am using VMS 4.1's SET HOST/DTE, and it works fine.  It uses quite a bit
less CPU time than KERMIT, VAXNET and the rest; it is also quite a bit less
"chunky" on the output.  Best of all you can send ^S when no output is
pending from the modem and not lock the thing up.

I was excited to see SYS$EXAMPLES:DTE_DF03.MAR; my recent (unsuccessful)
attempt at a UUCP <-> $MAIL gateway did some dialing, so I had the logic for
dialing a Hayes already finished and working...

So I wrote DTE_HAYES.C with a wrapper written in MACRO to do the .TRANSFER
and .MASK (neither of which I understand but the wrapper works, so...)  Then
I ran into some problems:

Just sending an ATDT command is not enough for our modem (not a "real" Hayes;
it doesn't watch DTR, so you can't assume it's offline when you start using it).
So I send (pause)+++(pause), ATH\r, expect OK\r\n, then send the ATDT#######\r
and expect CONNECT [1200] or NO CARRIER and return the appropraite status code
to VMS ("NO CARRIER" -> SS$_HANGUP).

Unfortunately I seem to be competing with VMS for the characters coming back
from the modem.  It's as though SET HOST/DTE sets up a half-dup connection from
the modem to my terminal before it calls my dialing code.  So when I send the
ATDT1234567\r command, the modem sends 1234567 as it dials the number, VMS
grabs and echos 12457 (or some subset) and my dialing logic only sees 36 (or
whatever VMS didn't grab).

I've tried cancelling IO on the modem channel before I start.  No go.  Just as
well, really, since I wouldn't know what to re-queue when I finished dialing.
I've thought of disabling ASTs at whatever level SET HOST/DTE operates in, but
I would still lose the first character sent by the modem.  I can kludge around
this as well, but I think I'll just send an SPR instead.

Side notes: someone on info-vax mentioned awhile ago that SET HOST/DTE sent
^Q out the modem port for every character it read or wrote or some such.  I've
been watching a DLM all day and I have yet to see any ^S or ^Q other than what
I type on my keyboard go out that modem port, so.....

A bug:  SET HOST/DTE (without a /DIAL) sends a CR out to the modem before
it sends the REM-I-TOEXIT message to your terminal.  With /DIAL this doesn't
happen.

Another bug: you can SET HOST/DTE to a terminal that someone is trying to log
into.  Very odd results on both terminals.

I'll let info-vax know if/when I ever get DTE_HAYES working; any other 
implementations or comments (HAYES or otherwise) are welcome.

	Paul Vixie
	dual!greipa!paul@ucbvax