AN2456 Datasheet, PDF (1/15 Pages) STMicroelectronics – Protection of single battery voltage SLICs for new networks in US market

AN2456
Application note
Protection of single battery voltage SLICs for new networks in US market
Introduction
Despite the widespread proliferation of digital technologies, analog networks remain the
most commonly used telecommunication means in the world. Thanks to its simple and
cheap technology, POTS (plain old telephone set) are still utilized extensively.
Figure 1. Schematic of new networks
Central Office / LT
Long lines
(Twisted pair)
Optical _{transmission RCO}
Short lines
(Twisted pair)
Optical ^transmission
Optical
Network
Unit
Central Office / LT
Figure 1 shows a schematic of modern telecom networks that are expected to keep
growing. These networks are essentially made up of two kinds of lines, classical long lines
(several kilometers long) that directly connect the Central Office (CO) to the subscriber, and
short lines (few tens of meters in length) that connect Remote Central Offices (RCO),
Optical Network Units (ONU) or Radio Network Units (RNU) to subscriber terminals. In
these networks SLICs can be present in either conventional Central Offices or any of the
above mentioned remote locations or in Remote Terminals (RT) in the customer premises
which connect to POTS through short lines. The link between these remote locations and
the CO is established by a long high speed digital link e.g. coaxial cable, fiber optic cable,
Wireless Local Loop (WLL). This disparity in line length has given rise to SLICs of two types.
Protection of both kinds of SLICs is a very important aspect in the design of the system. The
purpose of this application note is to propose a complete protection solution for short line
SLICs located in RT in customer premises.
November 2006
Rev 1
1/15
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