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From: EBERBERS%yubgef51@pucc.PRINCETON.EDU (____ Zarko Berberski ____)
Newsgroups: comp.sys.handhelds
Subject: RE: Using HP-48 with modem
Message-ID: <8FF4859C089F00011F@yubgef51>
Date: 12 Apr 91 22:56:26 GMT
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> And it seems the modem expects Ready To Send and
> Data Terminal Ready to be asserted --

      If HP-48 can communicate with computer with just TD/RD
lines then it can do the same with a modem. RTS/CTS is somethimes
used by some used by some communication software (and even in
some low-level OS routines) but modem doesn't need it. Same
applies to DTR but this signal is much more important and you
must use a micro-switch on your modem to force it to ignore DTR.
If you by any chance have so sophisticated modem (with internal
buffers, different in/out speed etc..) that can't live without
RTS/CTS then there must be a switch for this too. The general
rule is - you can always make modem as dumb as you like.

      But - you have to connect HP's TD to modem's RD and vice
versa (since modem and HP port are the same "type" of device).

            Zarko Berberski           EBERBERS@YUBGEF51.bitnet