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From: mlm@homxc.att.com (Mark L Milliman)
Newsgroups: comp.dcom.telecom
Subject: Re: Slick 96?
Message-ID: <2220@accuvax.nwu.edu>
Date: 16 Dec 89 20:47:02 GMT
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X-Telecom-Digest: Volume 9, Issue 578, message 5 of 7


Here is one additional reply to the many others on AT&T's SLC(r) 96
Subscriber Loop Carrier System.  SLC is a registered trademark of AT&T
Technologies, Inc.

As stated by others, the SLC 96 carrier system is a digital subscriber
carrier system that provides for up to 96 subscriber channels, when
fully equipped, between a central office terminal (COT) and a remote
terminal (RT).  The subscriber channels are pulse code modulated and
then time division multiplexed into DS1 (1.544 Mb/s) type signals.
The DS1 signals are then processed for transmission facilities.  In
addition to single and multiparty message telephone service, the
system can provide coin service, voice-frequency special services,
digital dataport service, and voice-data circuit switched digital
capabilities.

The system can operate in three modes:

	Mode I - Provides 96 dedicated lines over 4 T1 lines.
	Mode II - Concentrates groups of 48 lines onto 24 channels or 1 T1 
		  line.
	Mode III - Provides 48 special service, coin, or dataport channels
		   per system.

The signals can be transported between the COT and RT electrically or
optically at the DS1, DS2, or higher order optical rate.  This system
was introduced in the early '80's as an economical replacement to the
single copper pairs that run from the line card in the exchange to
each subscribers home.  Since that time a number of other vendors have
introduced similar systems to the SLC 96.  Because what once took 96
pairs of wires now takes 5 pairs (4 service and 1 protection), this
equipment is called a pair-gain system.

There is a sucessor to SLC 96 called SLC Series 5.  This new system is
similar to its predecessor but it serves twice as many subscibers in
the same space with less power.  It also has many enhanced features
over SLC 96.  One of those features is the capability to replace those
copper pairs that extend from the RT to the home with fiber optic
cable.


Mark L. Milliman			Internet:  mlm@homxc.att.com
AT&T Bell Laboratories			    UUCP:  att!homxc!mlm
Holmdel, NJ   07733
(201)949-0796				I want my ftp!