kenw@noah.arc.CDN (Ken Wallewein) (08/05/87)
Is here anyone out there who has managed to make US Robotics 9600 HST modems
work with a VAX/VMS 4.5 system? We have a couple here on trial. I have spent
too much time trying to make them work (using one as auto-answer dialup), and
it looks like I may have to just drop it.
I've tried about every parameter I can think of, both on the VAX and the
modem, dip switches and everything. Whatever the problem is, I'm pretty sure
-it's not obvious. I have a hardware/communications background, and do
understand RS-232. My test equipment includes a smart cable and a breakout
box. No communications monitor. I read the stuff that went out over the net a
few months ago about what VAX/VMS likes, and I half suspect that the problem
is due to logical 'holes' in the modem-handling state machine.
The problem seems to be partly due to the VAX's insistance on having CTS low
until DSR and DCD are high. The HST uses CTS strictly as hardware flow
control, and keeps it high until it wants to squelch something.
Jumpering CTS to DCD was no help. If I SET HOST/DTE to the port connected to
the VAX modem (the other is hooked to a terminal), it appears that I can
establish a connection, but no data goes through. Under some conditions, the
VAX modem (configured for auto-answer) will answer the phone and then
immediately hang up... or it might bring up carrier, maybe even wait until
the link is established, and THEN hang up. Either way, it starts up login
processed on the VAX. If the VAX port has DISCONNECT set, it starts up many
of there <login> processes, to the point that nobody else can log in until the
others time out, or I kill them.
I HAVE established the occasional working connection, but never twice in a
row. When it works, it works great. I haven't had a chance to try Kermit or
XMODEM, but terminal work is really good. 9600 baud screen output to the
screen. The keyboard response hesitates just a tiny bit - I'd say about 1/10
second, a lot less that using X.25 (Datapac).
When I called US Robotics (long distance to Illinois, no 800 number for us
unimportant Canadians, and I got the answering machine twice), I was told
that they can't be bothered to keep track of what works for all those different
(?!) DEC machines. No factual data as to what the HST wants and provides by way
of RS-232 protocols, except that bit about CTS being always up. I was not
impressed.
So far, I've talked to two people who are happy users of 9600 HST's, both
of them sysops of bulletin board systems.
I really can't spend much more time on these modems. I using one right now in
non-HST mode to a regular modem. It's supposed to automatically adapt to normal
modems, but I had to set it manually.
I think we'll be seeing a lot more of the 9600 HST. SOMEBODY has to figure
(or have figured) out how to do it. Has _anybody_ done it yet?
/kenw
A L B E R T A
Ken Wallewein R E S E A R C H
C O U N C I L