Table of Contents
Advertisement
6.5.1 HS Source and Composite Clock Cables on Backplane P/
N 850‑0330‑06/07
On systems with backplane (P/N 850‑0330‑06/07) the HS source and composite clock
cable (P/N 830‑0873‑xx) is used to transmit the clock outputs from the customer HS
source and composite clock sources to the EAGLE control shelf backplane, providing
the EAGLE with a second synchronized system clock. The EAGLE connects to the site
source clock through two DB 15 style connectors (J49 and J48) on the backplane of
the control shelf for primary and secondary clock signals. The two connectors are
labeled Primary BITS and Secondary BITS. Both primary and secondary clock signals
are sent to each terminal disk module (TDM). The TDM cards select between the
primary and secondary clock signals to provide A and B system clocks to the rest of
the EAGLE.
This procedure replaces the existing composite clock cables (P/N 830‑0226‑xx) with
RS422 compatible cables (P/N 830‑0873‑xx or P/N 830‑1189‑xx) connected to the
customer HS and composite clock sources.
Caution:
A system with DS0A links cannot run without a composite clock source. Take
extreme caution when replacing the composite clock source cables. Remove
one cable at a time and confirm between removals that the other composite
clock source is active.
Caution:
Perform this procedure during a maintenance window.
Caution:
Prior to adding or replacing the high‑speed source and composite clock
cables, perform an EAGLE system health check.
Caution:
HS clock alarms are only generated if an external BITS clock source is being
used.
Chapter 6
Source Timing
6-60
Advertisement
Table of Contents
