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From: leong%ANDREW@PT.CS.CMU.EDU (John Leong)
Newsgroups: mod.protocols.tcp-ip
Subject: re:  Bits, Bauds and Hz
Message-ID: <8601151600.AA00720@cmu-andrew>
Date: Wed, 15-Jan-86 10:59:15 EST
Article-I.D.: cmu-andr.8601151600.AA00720
Posted: Wed Jan 15 10:59:15 1986
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General Interest .....

T1 is the lowest TDM digital transmission rate used by the phone companies
for long line transmission. The standard bit rates are :

DS1  :  1.544M  (24 voice)@*
DS2  :  6.312M  (4 * DS1,  96 voice)@*
DS3  :  44.736M  (7 * DS2, 672 voice)@*
DS4  :  274.176M  (6 * DS3, 4032 voice)

Most DS1 or T1 data are done with twisted pairs. Fibre is normally used
only for DS4 or T4 data rate  which is heavily used for (real long distance)
inter-citiy traffics. 

Leong