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From: smb@ulysses.UUCP (Steven Bellovin)
Newsgroups: net.dcom
Subject: Re: 56Kbit telephone lines?
Message-ID: <771@ulysses.UUCP>
Date: Sat, 11-Feb-84 16:58:39 EST
Article-I.D.: ulysses.771
Posted: Sat Feb 11 16:58:39 1984
Date-Received: Tue, 14-Feb-84 01:03:53 EST
References: <2174@hplabs.UUCP>
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 37


	From: piety@hplabs.UUCP (Bob Piety)
	Newsgroups: net.dcom
	Subject: 56Kbit telephone lines?
	Message-ID: <2174@hplabs.UUCP>
	Date: Thu, 2-Feb-84 14:43:40 EST

	It seems that I've heard something about the telephone company (ies)
	offereing a 56K bit digital service.  Has anyone heard anything
	about it? Is it true? Available? When? Cost? Restrictions?

	Thanks in advance for your replies.

	Bob

Yup, it's true.  You're referring to CSDC (Circuit-Switched Digital Capa-
bility); it's 56Kb *dial-up* synchronous (and can also run at 9.6Kb, I think).
It will be available only at central offices that install some extra hardware
and new software for their ESS.  At the customer end, there's some box that
takes the place of a modem.  You can use the phone for voice or data calls;
the data calls must be preceeded by a special prefix.

As for availability -- to the best of my knowledge, the service has not
yet been tarriffed.  There are a few experimental installations in progress,
in (I think) Georgia, Florida, and N.J.

The real gotcha is that the service is syncronous.  There are protocol
converters available (for a few hundred dollars), but they don't go that
fast.  On the other hand, there hasn't been a market until now.  I'm following
this closely, because I'd like to have such a line to my house....

		--Steve Bellovin
		AT&T Bell Laboratories

P.S. I make no warranties as to the accuracy or reliability of the above
information.  It's my perception of reality, and has nothing to do with
any official policies of my employer.