[comp.unix.ultrix] How to do shared modem on DS200 terminal server from Ultrix?

D. Allen [CGL]) (09/11/90)

Anyone have a shared modem line working under Ultrix, say 3.1 or 3.1C,
via reverse LAT to a DS200/MC terminal server with attached modem?  My
getty keeps opening the line and engaging in a shouting match with my
modem and it thus won't let me tip to the modem.  Getty should *not* open
the line until a call comes in; it has to leave the line clear so I
can call out on it.

If this keeps up, I'll have to buy a Qbus serial card for my DS5400.
Or maybe I'll put the modems on our MicrovaxII; it has a serial card.

I thought terminal servers were supposed to be wonderful?

grr@cbmvax.commodore.com (George Robbins) (09/11/90)

In article <9009110234.AA18245@watcgl.waterloo.edu> idallen@watcgl.uwaterloo.ca (Ian! D. Allen [CGL]) writes:
> Anyone have a shared modem line working under Ultrix, say 3.1 or 3.1C,
> via reverse LAT to a DS200/MC terminal server with attached modem?  My
> getty keeps opening the line and engaging in a shouting match with my
> modem and it thus won't let me tip to the modem.  Getty should *not* open
> the line until a call comes in; it has to leave the line clear so I
> can call out on it.

I'd make sure that the modem is set up so that it doesn't make with
carrier detect/data set ready until an incoming call is in progress
and that the terminal server has appropriate modem control settings.

Even so, I'm not sure you can get it to work - terminal servers put lots
of code where once simple wire was, and truely transparent it ain't.

> If this keeps up, I'll have to buy a Qbus serial card for my DS5400.
> Or maybe I'll put the modems on our MicrovaxII; it has a serial card.

Might not be a bad idea, if you're trying to use fast modems you may
run into thruput/buffering problems or other irritations.

> I thought terminal servers were supposed to be wonderful?

B.S.
-- 
George Robbins - now working for,     uucp:   {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing:   domain: grr@cbmvax.commodore.com
Commodore, Engineering Department     phone:  215-431-9349 (only by moonlite)

thomas@mipsbx.lkg.dec.com (Matt Thomas) (09/14/90)

In article <9009110234.AA18245@watcgl.waterloo.edu> idallen@watcgl.uwaterloo.ca (Ian! D. Allen [CGL]) writes:
>Anyone have a shared modem line working under Ultrix, say 3.1 or 3.1C,
>via reverse LAT to a DS200/MC terminal server with attached modem?  My
>getty keeps opening the line and engaging in a shouting match with my
>modem and it thus won't let me tip to the modem.  Getty should *not* open
>the line until a call comes in; it has to leave the line clear so I
>can call out on it.

But _init_ doesn't know when a call came in so it doesn't know when to
fork/exec a getty.  I wish it did if you do it for LAT, then you'll want to
do it for every other terminal device.  But it doesn't, so it has to start a
getty on that line.  But that is set for outgoing calls too.  Which means
the getty starts up and connect to DS200 and the modem just like you were
dialing out (since LAT doesn't know the difference).

You can consider LAT to a terminal with nomodem control and that the cable
is cut when the user is finished.  (A new cable is strung when the next user
logs in).  Since shared is only supported on ttys with full modem-control,
it won't work on LAT.

>If this keeps up, I'll have to buy a Qbus serial card for my DS5400.
>Or maybe I'll put the modems on our MicrovaxII; it has a serial card.

I think the DHQ11 is supported.

>I thought terminal servers were supposed to be wonderful?

Only for some things.   Note that if you were going to run UUCP or some
other program and has a lot of input, then you really want a local device
as it respond faster to flow control.  Note that if it possible, configure
for hardware flow control on the port.


Matt Thomas                     Internet:   thomas@wrl.dec.com
DECnet-ULTRIX Development       UUCP:       ...!decwrl!thomas
Digital Equipment Corporation   Disclaimer: This message reflects my own
Littleton, MA                               warped views, etc.

D. Allen [CGL]) (09/15/90)

>You can consider LAT to a terminal with nomodem control and that the cable
>is cut when the user is finished.  (A new cable is strung when the next user
>logs in).  Since shared is only supported on ttys with full modem-control,
>it won't work on LAT.

Wot?  You mean I bought three DS200/MC units with modem control and
the modem signals are not propagated back to the Ultrix ttys?  What's
the point of modem control on the DS200 then?
-- 
-IAN! (Ian! D. Allen) idallen@watcgl.uwaterloo.ca idallen@watcgl.waterloo.edu
 [129.97.128.64]  Computer Graphics Lab/University of Waterloo/Ontario/Canada

jv@mh.nl (Johan Vromans) (09/15/90)

In article <1990Sep15.053123.21371@watcgl.waterloo.edu>
idallen@watcgl.waterloo.edu (Ian! D. Allen [CGL]) writes:

   Wot?  You mean I bought three DS200/MC units with modem control and
   the modem signals are not propagated back to the Ultrix ttys?  What's
   the point of modem control on the DS200 then?

I agree, Ian, this is ridiculous!

Also, in article <15364@shlump.nac.dec.com> thomas@mipsbx.lkg.dec.com
(Matt Thomas) writes (in reply to Ian):

   Ian> If this keeps up, I'll have to buy a Qbus serial card for my DS5400.
   Ian> Or maybe I'll put the modems on our MicrovaxII; it has a serial card.

   I think the DHQ11 is supported.

DEC advised me to buy a DS5000 instead of a DS5400 (which I did). And
a 5000 does not have anything alike a DHQ11.
I feel disappointed.

	Johan
[The above opinions are my own, but I think it won't cost much effort
 to make my boss share them.]
-- 
Johan Vromans				       jv@mh.nl via internet backbones
Multihouse Automatisering bv		       uucp: ..!{uunet,hp4nl}!mh.nl!jv
Doesburgweg 7, 2803 PL Gouda, The Netherlands  phone/fax: +31 1820 62911/62500
------------------------ "Arms are made for hugging" -------------------------

grr@cbmvax.commodore.com (George Robbins) (09/16/90)

In article <1990Sep15.053123.21371@watcgl.waterloo.edu> idallen@watcgl.waterloo.edu (Ian! D. Allen [CGL]) writes:
> >You can consider LAT to a terminal with nomodem control and that the cable
> >is cut when the user is finished.  (A new cable is strung when the next user
> >logs in).  Since shared is only supported on ttys with full modem-control,
> >it won't work on LAT.
> 
> Wot?  You mean I bought three DS200/MC units with modem control and
> the modem signals are not propagated back to the Ultrix ttys?  What's
> the point of modem control on the DS200 then?

Basic modem control *is* supported, i.e. CD to detect hangups and probably
DSR to enable/disable answer, but that doesn't mean the emulation is good
enough to support the Ultrix flavor of shared modem support (though it might
work).  You may also have problems with things like "send break" or having
to hit return to establish an incoming connection, which may or may not be
a problem for your intended use.

-- 
George Robbins - now working for,     uucp:   {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing:   domain: grr@cbmvax.commodore.com
Commodore, Engineering Department     phone:  215-431-9349 (only by moonlite)

thomas@mipsbx.lkg.dec.com (Matt Thomas) (09/16/90)

In article <1990Sep15.053123.21371@watcgl.waterloo.edu> idallen@watcgl.waterloo.edu (Ian! D. Allen [CGL]) writes:
>>You can consider LAT to a terminal with nomodem control and that the cable
>>is cut when the user is finished.  (A new cable is strung when the next user
>>logs in).  Since shared is only supported on ttys with full modem-control,
>>it won't work on LAT.
>
>Wot?  You mean I bought three DS200/MC units with modem control and
>the modem signals are not propagated back to the Ultrix ttys?  What's
>the point of modem control on the DS200 then?

Such that when the user logs off, the DECserver detects the change and
kills all of his sessions.  Or so that you can do hardware (CTS/RTS or 
DSR/DTR) flow control.

Under LAT, modem control signals are not communicated up to the host.  They
are dealt with entirely by the terminal server (with the end result being
propogated to the host -- if needed).

Matt Thomas                     Internet:   thomas@wrl.dec.com
DECnet-ULTRIX Development       UUCP:       ...!decwrl!thomas
Digital Equipment Corporation   Disclaimer: This message reflects my own
Littleton, MA                               warped views, etc.