How to do shared modem on DS200 terminal server from Ultrix?

Matt Thomas thomas at mipsbx.lkg.dec.com
Fri Sep 14 12:50:29 AEST 1990


In article <9009110234.AA18245 at watcgl.waterloo.edu> idallen at 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 at wrl.dec.com
DECnet-ULTRIX Development       UUCP:       ...!decwrl!thomas
Digital Equipment Corporation   Disclaimer: This message reflects my own
Littleton, MA                               warped views, etc.



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