A-3
Cisco VISM Installation and Configuration Guide
Release 3.0, Part Number OL-2521-01 Rev. D0, June 2004
AppendixA VISM and VISM-PR Card Clocking Options
VISM Card as Primary Clocking Source
VISM Card as Primary Clocking Source
Figure A-2 shows the VISM card primary clocking source option in which the clock source originates
at the VISM side of the VISM/PXM interface.
FigureA-2 VISM Configured for Loop Clocking
The VISM card option originates clocking from one of th e T1 or E 1 lin es on one of t he V ISM c a rds .
To configure the VISM card as the primary clocking source, complete the following steps:
Step 1 Use the cnfln command to configure line number 1—the line that is receiving the clocking source—for
loop clocking.
Step 2 Use the cnfln command to configure all remaining T1 or E1 lines on all VISM cards in the chassis for
local clocking.
Step 3 Use the cnfclksrc command to configure the PXM card as a servic e module clocki ng sourc e and specif y
VISM and its clocking line (line number 1) as the clocking source.
Note The VISM card allows you to configure the clock source on line 1 only. The VISM-PR card does n ot
have this requirement.
VISM-PR Card as Primary Clocking Source
The VISM-PR card allows you to configure primary clocking from the fol lowing sourc e s:
•Network clock—the local clock for the PXM1, PXM1E, or PXM45 module
•Any VISM-PR T1 or E1 line
•On-board oscillator
External BITS (T1/E1
)
Network (OC3)
Internal crystal
Clocking on T1/E1
line 1 to
PBX or CO
MGX 8850
VISM
V
ISM line #1 configured
f
or loop clocking, all other
V
ISM lines (including all
l
ines on other VISM cards)
c
onfigured for local clocking MGX clock source configured for:
Service Module
Bus
51225