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Line cards 43
Off-premise line protection
Off-premise applications are installations where the telephone lines are
extended outside the building where the PBX system is housed, but the lines
are not connected to public access facilities. This application is commonly
referred to as a "campus installation."
In off-premise applications, special protection devices and grounding are
required to protect PBX and telephone components from any abnormal
conditions, such as lightning strikes and power line crosses.
The NT1R20 Off-Premise Station Line card has built-in protection against
lightning strikes and power line crosses. These should be the preferred
cards for an off-premise application. Other cards can be used when external
line protectors are installed.
When using the Lineside T1 card for an off-premise or network application,
external line protectors must be installed. Install an isolated type Channel
Service Unit (CSU) as part of the terminal equipment, to provide the
necessary isolation and outside line protection. The CSU should be an
FCC part 68 or CSA certified unit.
Line protectors
Line protectors are voltage-absorbing devices that are installed at the
cross-connect terminals at both the main building and the remote building.
The use of line protectors ensure that system and telephone components
are not damaged from accidental voltages that are within the limit of the
capacity of the protection device. Absolute protection from lightning strikes
and other stray voltages cannot be guaranteed, but the use of line protection
devices significantly reduces the possibility of damage.
Nortel has tested line protection devices from three manufacturers. See
Table 5 "Line protection device ordering information" (page 43). Each
manufacturer offers devices for protection of digital as well as analog
telephone lines.
Table 5
Line protection device ordering information
Device order code
Analog Line Digital Line Manufacturer
UP2S-235 UP2S-75 ITW Linx Communication
201 Scott Street
Elk Grove Village, IL 60007
(708) 952-8844 or (800) 336-5469
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
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