Installing the CBX 500 Switch
Connecting External Clock Inputs and Outputs
Beta Draft Confidential
4-16
4/5/03
CBX 500 Multiservice WAN Switch Hardware Installation Guide
Connecting External Clock Inputs and Outputs
This section describes how to connect an external clock source for either T1 or E1.
Follow the instructions in this section only if you want to use an external clock source
for your switch network.
There are five possible timing sources for the active SP:
Two external clocks — The external clock inputs can accept timing from an external
high-accuracy source.
Two IOP-module derived sources — The SP has a timing subsystem that manages
all aspects of locking and distribution of the clock to each of the IOP modules.
Internal clock source with Stratum accuracy — If the selected clock sources fail,
the system is automatically reconfigured so that it is synchronized with the SP’s
internal clock (which has Stratum 3 accuracy).
T1 Clock Connection
The T1 timing inputs work with DS1 timing references that comply with the ANSI
T1.102 standard. The T1 timing output takes its timing source from a selected clock
source configured via the NMS.
The SPA panel on the back of the switch contains three sets of wire-wrap pins for
connecting the following:
•
An external T1 clock input
•
A redundant external T1 clock input
•
A T1 clock output
