Nortel Passport 15000, Установка и обслуживание оборудования, Страница: 79 / 874

Chapter 4 Alarm/BITS module 79
Passport 15000, 20000 Hardware Installation, Maintenance, and Upgrade 5.2S2
Timing cable installation
Install the required timing cables after initial installation to enable external
timing functionality on a Passport 15000 or 20000.
• “Prerequisites to timing cable installation” (page 79)
• “Timing cable installation task flow” (page 79)
Prerequisites to timing cable installation
• A timing cable refers to the cable that runs from the external timing
source to the alarm/BITS module or to one of the prefabricated cable
assemblies connected to the module.
• Your choices for timing cable installation include:
— two pairs of wires from the site BITS source, one pair to each
connector on the alarm/BITS module, providing full redundancy
— one pair of wires from the site BITS source split to each connector
on the alarm/BITS module, providing redundancy only inside the
switch
— one pair of wires from the site BITS source to one connector on the
alarm/BITS module, providing no redundancy
• You need one of the following cable assemblies:
• Some versions of the alarm/BITS module on either a Passport 15000 or
20000 have prefabricated cable assemblies that connect to the module at
one end and connect to the site BITS timing source at the other end. Since
the alarm/BITS module is pre-installed at the factory, so are its
prefabricated cable assemblies. There are two cable assemblies per
module for redundant timing signal input.
Timing cable installation task flow
This task flow shows the sequence of procedures to install a timing cable. To
link to any procedure, go to “Task flow navigation” (page 80).