Path: utzoo!telecom-request
Date: Fri, 3 May 1991 18:51:37 GMT
From: Bud Couch <kentrox!bud@uunet.uu.net>
Newsgroups: comp.dcom.telecom
Subject: Differences in T1/E1 Standards
Message-ID: <telecom11.332.12@eecs.nwu.edu>
Organization: Kentrox Industries, Inc.
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In article <telecom11.323.5@eecs.nwu.edu> nanook@eskimo.celestial.com
(Robert Dinse) writes:

> used in this country. The normal T1-cxr uses 64kb/s (8 bits times 8
> Khz sample).

>> 20 phone calls take 1 Mb/s (actually, T1 line at 1 Mb/s handles 32

>     The standard T1 rate is 1.544 Mbits/sec and carries 24 not 32
> channels.

I think that the confusion lies in the difference between US (and Japan)
*T1* rates and the CEPT (European *E1* standards. Both use a channel rate
 of 64 Kb, but not the same frame, signaling, or channel structure. T1
uses 24 channels of 8 bits, whereas the CEPT systems have 32 channels
of 8 bits.  Only 30 of those are used for end-to-end transmission, the
remaining two channels are for signaling, framing and maintenence. The
E1 line rate is 2.048 Mb/s. T1 has an extra bit assigned for framing,
etc, and may steal an lsb from each channel for signaling every sixth
frame.


Bud Couch - ADC/Kentrox    If my employer only knew ...  standard BS applies