[comp.dcom.modems] bridge vs modems

haque@umn-cs.UUCP (03/11/87)

greetings fellow netlanders.. :-)

I have a set up of two Bridge CS/100T's acting as entrylevel gateways
for our local area network of TCP/IP machines. We are currently
running an estimated 30 sun workstations, a Vax 11/780, a DG MV/10000
IBM PC network , HP Unix machines and such..

The problem I have currently lies with our dial-in facilities with
these particular bridge boxes. 

	Actually I should mention that our University (of Minnesota, MPLS) 
recently switched over to a super-duper phone system [all electronic and 
computerized state of the art] using IBX equipment. We have been
having problems with the system, but not in any consistent manor.

So, what our bridges have hooked up to them are BIZCOMP modem, these
are *intelligent* Hayes compatible modems. Now, when you dial in to
these modems, at 300/1200 you can get connected over 80% of the time.
But during the other 20 %, the modem is usually *off the hook*

This behaviour is puzzling. Suddenly without apparent warning, the
modems seem to get a signal from the bridge saying, "get ready for
command input, take phone line off the hook, and stay until told so"

The bridges do have a sort of crude getty running on them, so there is
a transfer of characters toward the modem, but what would make the
BIZCOMP modem, upon receipt of the "CS/100T_1>" prompt , go into input
mode, beats me.

For those of you who have dial in bridges, how and what setup are you
using?? Please, Please give me some information on what the bridge
boxes like or not.. Dis is driving me nuts.. since the only method to
correct is actually disconnecting the rs 232 link and power cycling
the modem.
 Also, are you thinking of providing services for 300/1200/?2400?
users, since the price of 2400 modems is getting affordable. So far as
I can see, the bridge boxes can only handle 300/1200 or
1200/2400/4800/9600. :-(

By the way, the bridge software I am running is ver 13002 of the
TCP/IP code.
				Thanks a lot.
				Samudra Haque
				Computer Science Systems Group
				University of Minnesota, Minneapolis
				(612) 625 0876
				haque@umn-cs.ARPA or haque@umn-cs.UUCP

scarter@caip.UUCP (03/12/87)

In article <83700001@umn-cs.UUCP> haque@umn-cs.UUCP writes:
>
>
>The problem I have currently lies with our dial-in facilities with
>these particular bridge boxes. 

You may want to try to set those ports for auto-parity, auto-baud.  The
chances of getting a CR-period-CR in a string of garbage is slim.  I suspect
that noise is starting up a connection and then the cs/100 and the modem
start playing ping-pong.  I am not familiar with your modem, but could
something in your welcome string or prompt (ie a ^J,^M,etc) put the modem
in active mode?  (Be sure you warn your users before you do this).

Also you should set the inactivity timer for those ports to some small number
of minutes.  Sometimes, users will logout of the host system and pull the 
plug on the modem.  The cs/100 will sit there for 15 minutes (the default)
before it will go into listen mode, and drop CD, depending on how you have
the dtrin parameter set.

> Also, are you thinking of providing services for 300/1200/?2400?
>users, since the price of 2400 modems is getting affordable. So far as
>I can see, the bridge boxes can only handle 300/1200 or
>1200/2400/4800/9600. :-(
>

This is a firmware issue rather than a software issue.  We have been raising
hell with Bridge on this since day 1.  As of six months ago, it was in the 
"to be added feature list".   Start demanding it...  They have full 
auto-bauding on the cs/200, so at least they have the code.  I think it is
a "marketing issue"....