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From: rjn@hpfcmp.HP.COM (Bob Niland)
Newsgroups: comp.sys.hp
Subject: Re: Modem control on HP 9000 Series 520
Message-ID: <1260001@hpfcmp.HP.COM>
Date: Wed, 17-Dec-86 14:55:55 EST
Article-I.D.: hpfcmp.1260001
Posted: Wed Dec 17 14:55:55 1986
Date-Received: Sat, 20-Dec-86 22:43:19 EST
References: <458@rayssd.RAY.COM>
Organization: Hewlett-Packard, Ft. Collins CO
Lines: 31

re:  "I have been trying to set up a HP 9000 Series 520 and have ran into a
      problem.  Modem control.  It is hook up to a port selector and will
      not drop carrier.  How does one get it to drop carrier?  Does it take
      an hardware change or can it be done in software?"

Cases:

* If you are using the 27130A/B 8 channel MUX, it can't be done.  Each port
  on an 8MUX is 3-wire only.  CD is wired high and cannot be controlled.

* If you are using a 27128A Async Serial Interface (ASI), it depends on the
  cable - Option 001 (DTE) or Option 002 (DCE).   We are successfully using
  ASIs here to talk to an INFOTRON port selector.

* If you are using a 27140A 6 channel MUX, it again depends on the cable.
  Each port "sort-of" looks like a DCE, and can be converted to DTE via 
  the 92219Q cable.   We are using a non-standard cable to talk to our
  INFOTRON.

We should be able to assist you.  Let us know what interface (and cable) you
are using, identify the brand and model of port selector, and if possible,
provide more detail about what lines and handshake are expected by the port
selector.

Finally,  if your system has either RCS (Response Center Support) or AMS
(Account Management Support) service, you should be able to get questions
like this answered much more quickly than using news/notes.

Regards,                                              Hewlett-Packard
Bob Niland                                            3404 East Harmony Road
[ihnp4|hplabs]!hpfcla!rjn                             Fort Collins CO  80525