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From: hingston@apple.com (Joe Hingston)
Newsgroups: comp.dcom.telecom
Subject: ISDN-Modem Interworking Question
Message-ID: <4296@accuvax.nwu.edu>
Date: 23 Feb 90 22:36:18 GMT
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X-Telecom-Digest: Volume 10, Issue 124, Message 2 of 11


What is going to be the common (and/or correct) way to interwork ISDN
terminals with services that are modem based?  I am thinking of
personal computers with ISDN as a built in feature, or with an ISDN
add-in card.

I can think of a couple of obvious ways, but do not know which will be
used, or indeed if some totally different means will be used.

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.

2) The ISDN terminal will use some form of rate adaptation, similar to
V.110.  But then who converts the rate adapted bit stream to modem
tones? The phone company?  A third party?

3) Almost the same as 2), but instead of bit rate adaptation data is
sent as HDLC frames.  This raises the same questions as to who
converts the frames to tones.

Are the RBOCs allowed to do the rate adaption, or does it fall into
the category of protocol conversion?  Will there be pools of Rate
Adaptors, similar to the modem pools that currently exist?

I hope these questions make sense, if not please feel free to suggest
new questions.


A screaming comes across the sky"  T. Pynchon
These statements in no way reflect Apple opinions.
Joe Hingston (hingston@apple.com)