Nortel Passport 15000, Установка и обслуживание оборудования, Страница: 743 / 874

Chapter 17 Hardware procedures 743
Passport 15000, 20000 Hardware Installation, Maintenance, and Upgrade 5.2S2
Removing a timing cable for DS1 NTHW75
Remove a wire-wrap timing cable NTHW75 to replace it.
Prerequisites
• You must be familiar with “Safety considerations and best practices”
(page 53).
• Inform the software network operator that disconnecting the cable to
replace it will generate software alarms.
Procedure steps
1 Note the path of the old cable assembly.
2 Unplugging either end of the cables at J3 or J4 generates software alarms
for loss of primary timing signal and a switchover to the secondary (if
configured and available), or a loss of the secondary as a backup timing
reference. For information about BITS alarms, refer to 241-5701-500
Passport 6400, 7400, 15000, 20000 Alarms.
3 Unfasten the captive D-sub connector screws and unplug the ends of the
old cable assembly from the alarm/BITS module.
4 Remove the terminal cover from the wire-wrap terminal block. See the
figure “A timing cable assembly NTHW75 and terminal connections”
(page 744).
5 Remove the wire wrapped ends of the old cable assembly from the pins
on the terminal block, noting the pins that were used for the connections.
6 Remove the old cable assembly from any cable management brackets on
the frame and put it aside.