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4-8
Chapter 4 - Maintenance and Troubleshooting
CO Line Card Functions
The Loop Start CO Interface Board provides loop start line interface from the Public Telephone
Network to provide ringing and loop start flash.
6 or 8 Loop Start CO lines on the
system are not working ...
CO Line(s) are not ringing ...
Noise or Crosstalk on the line. (CO
Line checks fine at demarcation
point with system isolated) ...
CO Button not working ...
PRIB/BRIB ISDN and T1IB are digital CO interface boards.
Popping, crackling, dropped calls,
or one-way transmission ...
Table 4-5: Loop Start CO Interface Board (LCOB)
Problem
Table 4-6: PRI/BRI ISDN and T1
Problem
Peripheral Cards and Components
Possible Solutions
Check wiring.
Try a replacement LCOB to identify if card
is defective.
Check programming.
Check CO Line Ring Assignment in
programming.
Check whether CO lines are bundled too
tightly.
Try a replacement LCOB to identify if card
is defective.
Check wiring.
Check programming of CO lines.
Possible Solutions
Verify the following settings and
connections:
The LD1 on the MPB is lit.
The clock source switch on the LMU1 is
set correctly for the external clock
source being used.
The clock cables are connected
correctly.
The clock switches on the BRIB/PRIB/T1
are set correctly.
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Table of Contents
Troubleshooting
