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From: qeds@mtuxo.UUCP (e.schulz)
Newsgroups: comp.dcom.modems
Subject: Re: Pending FCC ruling threat to modem users
Message-ID: <2357@mtuxo.UUCP>
Date: Fri, 26-Dec-86 22:19:17 EST
Article-I.D.: mtuxo.2357
Posted: Fri Dec 26 22:19:17 1986
Date-Received: Sat, 27-Dec-86 05:37:01 EST
References: <1572@brl-adm.ARPA> <3454@curly.ucla-cs.UCLA.EDU> <403@pixar.UUCP> <1496@kitty.UUCP>
Organization: AT&T Information Systems Labs, Holmdel NJ
Lines: 23
Keywords: modems, bandwidth, carrier, TASI

I was a member of the TASI-E development team at AT&T Bell Labs
from 1979 to 1982, and can confirm that as far as I know, Larry
Lippman's comments about TASI are correct.  Advances in digital
radio, fiber-optic cable, and other technologies keep driving the
cost of long-distance facilities down; this keeps TASI from proving
in domestically.  There are at least two dozen TASI-E systems in
use on undersea cable (last I heard), each with a capacity of about
240 conversations on 120 long-distance circuits.

The front-end clipping of speech bursts is barely noticeable to the
trained ear on TASI-E.  How we achieved this and tested it in field
trials is interesting, but not for comp.dcom.modems!

TASI-E does detect the echo-suppressor disable tone at the start of
a data call, and "pins up" the connection (does not do TASI) for the
duration of that call.  If overseas modem (and fax and music on
hold) traffic exceeded 5% or so, the TASI advantage would be
reduced, those routes would need to be re-engineered, and eventually
overseas phone service would cost more.  Not domestic service,
though.
-- 
Ed Schulz, AT&T Information Systems, Middletown, NJ
(201)957-3899 {at&t}!solar!eds