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 Tue, 10 Dec 1991 18:34:57 -0500
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Date: Tue, 10 Dec 1991 18:34:55 -0500
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Subject: What is ISDN Good For?
From: mkapor (Mitch Kapor)
Sender: ckd

habs@panix.com (Harry Shapiro) writes:

"What applications that require ISDN can't already run with existing
products like switched 56 kbit, and 14,400 modems?"

Switched 56 kilobit service has the same order of bandwidth as 64 kbit
ISDN, but its availability is strikingly different.  Switched 56 is not
intended to be a residential service.  Our vision of ISDN is that you
simply order it the way you order an additional voice-grade phone line.
Further, we believe ISDN must be priced like voice telephone service.
Switched 56 is not priced like voice service.  It is much more
expensive.  ISDN must be ubiquitous and affordable.  Switched 56, while
useful for businesses which can afford expensive installation and fees
is not.

The ISDN rate of 64 kb is at the critical threshold which will permit
interactive multimedia using video and audio compression.  14.4 is
simply too slow, even with compression, for videotelephony, much less
other more demanding forms of video.  Before it is argued that the
effective rate of a V.32bis modem is not 14.4 kb, but 14.4 kb plus
compression effects, let me point out that the same compression
techniques can and will be applied over 64 kb ISDN lines, boosting its
effective rate by an equivalent factor of two to four.

While it is still considered heretical in some quarters to assert that
VHS-quality video will be possible over a 64 kb line, there is a growing
consensus among researchers at the cutting edge of work in this area
that that is exactly where we are headed.  In such a scenario, using
desktop personal computers of the year 1995 as video production studios,
everyone with access to a PC and ISDN potentially becomes a video
producer, with ISDN as the switched distribution network providing video
dial-tone.  This will open the floodgates of innovation in video,
acheiving the richness of video (not passive, but interactive) with the
type of diversity heretofore associated only with print.

Beyond ISDN are other protocols which can run over copper-pairs, such as
ADSL, which runs at 300 kb /second.  More on that later.

Mitchell Kapor
Electronic Frontier Foundation