Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!mintaka!bloom-beacon!eru!hagbard!sunic!liuida!indic.se!zap
From: zap@indic.se (Jonas Petersson)
Newsgroups: comp.sys.hp
Subject: Re: Hardware flow control on 9k/800s
Summary: strange HST
Keywords: HST MUX 825 835 425 300 cu kermit
Message-ID: <1991May25.185609.25891@indic.se>
Date: 25 May 91 18:56:09 GMT
References: <1991May22.164645.5002@vax5.cit.cornell.edu>
Distribution: comp
Organization: Indic Computerised Air Quality Surveillance
Lines: 42

In article <1991May22.164645.5002@vax5.cit.cornell.edu> asfy@vax5.cit.cornell.edu writes:
>We have an HP 9000/825, with a 98196A 6-channel mux card
>installed.  We're running HP/UX 7.0.  We're looking into the
>possibility of installing a US Robotics HST modem on this
>machine, and it would be best to use full duplex hardware flow
>control on the RTS and CTS lines.  I don't see anything in the
>manuals-- does anybody know if it can be done? 

I can tell you one thing: It works, but in a strange way. I have successfully
used HST modems on a 825/835 (upgraded lately) and when it works, it
works like a champ. However, sometimes the modem refuses to answer. It didn't
happen too often and I usually have 'ct' call me back anyway after loggin in
on a different line.

As we bought a 425S for a cluster server instead, I've noticed that a
similar (same?) problem is repeatable (on all tried 3/400 series MUXes):

* RTS is lowered at boot time and by 'cu' which makes the modem refuse 
  to answer.

I've figured out two workarounds:
  
   1) Run a program that raise RTS now and then. Kermit works for instance.

   2) Configure the modem to ignore RTS in some way (there is a zillion
      soft switches as you know). This wasn't needed on the 8x5 though.

Neither is very good since 1) really shouldn't work, and 2) isn't too
nice for HW flow control - seems to work though.

I've reported this to HP Sweden, and they tell me that it is supposed to
be like this - that is: 'cu' *SHOULD* leave RTS low on exit regardless of 
what it was when 'cu' started. How anybody should be able to log in after 
that beats me... 'cu' was this way in 7.0.

		Good luck / Jonas Petersson

-- 
     ///  "Are you THE Zaphod Beeblebrox ????" # zap@indic.se
__  ///                                        # Air Quality Surveillance
\\\///    "No, just A Zaphod Beeblebrox.       # "I can feel it coming 
 \///  Didn't you hear - I come in sixpacks !" #   in the air..."