From: bcapps@atlastele.com (Brent Capps)
Subject: Re: The ISDN network
Organization: Atlas Telecom Inc.
Date: Fri, 11 Dec 1992 01:34:46 GMT

In a previous article Jim.Rees@umich.edu writes:
>In a previous article bcapps@atlastele.com (Brent Capps) writes:
>
>> An ISDN set won't talk to an analog modem.  An engineer might call this a
>> deployment issue WRT the modem, but the end user is going to see it as a 
>> technical impediment.  Exclusively using ISDN for your home PC effectively 
>> cuts you off from BBS, etc., which makes it kinda hard to justify its use.
>
>There isn't anything about ISDN that prevents you from using a modem with
>it, although you have to provide your own analog conversion (which is why
>ISDN should be tarriffed cheaper than analog lines).  Most ISDN terminal
>equipment even comes equipped with rj-11 jacks so you can plug in analog
>equipment without buying a separate ISDN voice set.  

I wasn't talking about the modem on your end, but the one on the other end.
I never said you couldn't plug a modem into a TA on your end, but who in
their right minds will want to shell out $$$ for the CPE and $$ monthly
for the ISDN service once they realize they're still going to be dependent
on an analog fax/modem to talk to 99.997% of the world?

So here's the situation.  I've got a modem plugged into a TA on my
premises when a call comes in.  How do I determine whether the caller is
analog or digital?  I can't listen for tones, because modem tone is
supposed to be generated by the *receiving* party. 

>Eventually someone will even offer a digital ISDN modem, which will be 
>cheaper to manufacture than an analog modem.

Great, what a technological leap forward that will be.  I'm so glad we
spend billions developing and deploying ISDN so we could continue to
communicate using modems to get our real work done.

And toense@cplxsys.ncsl.nist.gov (Robert E. Toense) writes:

> While this is possible, I would hardly ever see it done.  It is silly to do 
> conversion from digital data to analog, to digital, to analog, to digital ... 
> (get my drift).

If you work around automated ISDN calling equipment you're going to see this
all the time.  If I have an ISDN box that automatically delivers fax or ASCII 
messages it's going to have a hell of a time determining on a per-call basis
whether to deliver a message via analog or digital form.

> As for dial-in services, I would expect that they would have analog lines for
> modem service and ISDN lines for pure digital service.  The mix would be
> based on the needs of their customers and other business factors.

So you've got to know in advance whether a number you're calling is analog 
or digital?  How are you supposed to deliver a fax on this basis?  Can you 
imagine how irritating that's going to be for end users?

Unless it can get beyond market barriers like these, there isn't going to be
any demand for ISDN for anything beyond point-to-point dialup file transfer. 

> The analog phone and the modem will be around for some time -- just
> like the crank telephone.

Probably a lot longer than ISDN at this rate.
-- 
Brent Capps                          | 
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