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From: gnu@toad.com (John Gilmore)
Newsgroups: comp.dcom.telecom
Subject: Re: ISDN-Modem Interworking Question
Message-ID: <4605@accuvax.nwu.edu>
Date: 1 Mar 90 11:24:24 GMT
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X-Telecom-Digest: Volume 10, Issue 135, Message 7 of 7


hingston@apple.com (Joe Hingston) wrote:

> 1) The ISDN terminal will have a standard modem sitting behind a
> codec.  As far as the network and the service provider are concerned
> ISDN does not need to exist.

Even better -- the ISDN terminal can have a SOFTWARE modem implementation 
and a SOFTWARE codec.  Why add hardware just to talk to old equipment?
Certainly a low speed (<= 2400 baud) modem should be doable on today's
CPUs.  If you have a DSP, the whole ball of wax up through Telebits is
no problem.

Actually the ISDN end will be aware that ISDN exists.  But it will
dial into a 'voice' line on the other end that happens to have an old
style modem attached to it, in the same way that an ISDN voicemail
system might call a voice phone to forward a call to you.  The other
end will just think it's talking to a standard modem.

No phone company politics, 'rate adaptation', etc needed.

Of course, anyone with the right computers could offer such a service
to the public -- e.g. you phone me with ISDN protocols, I phone
somebody else with old-modem protocols and relay the data.  It could
even be done in its spare time by your IBM PC on a single phone line
(since a single ISDN line has two 64kbit data channels that work
independently).