User's Manual Part 3

C–CCP Backplane Troubleshooting
Mar 2001
6-13
SCt4812T CDMA BTS Optimization/ATP
DRAFT
Introduction
The C–CCP backplane is a multi–layer board that interconnects all the
C–CCP modules. The complexity of this board lends itself to possible
improper diagnoses when problems occur.
Connector Functionality
The following connector overview describes the major types of
backplane connectors along with the functionality of each. This
information allows the CFE to:
 Determine which connector(s) is associated with a specific problem
type.
 Isolate problems to a specific cable or connector.
Primary “A” and Redundant “B” Inter Shelf Bus Connectors
The 40 pin Inter Shelf Bus (ISB) connectors provide an interface bus
from the master GLI2 to all other GLI2s in the modem frame. Their
basic function is to provide clock synchronization from the master GLI2
to all other GLI2s in the frame.
The ISB also provides the following functions:
 Span line grooming when a single span is used for multiple cages.
 MMI connection to/from the master GLI2 to cell site modem.
 Interface between GLI2s and the AMR (for reporting BTS alarms).
Span Line Connector
The span line input is an 8–pin RJ–45 connector that provides a primary
and secondary (if used) span line interface to each GLI2 in the C–CCP
shelf. The span line is used for MM/EMX switch control of the Master
GLI2 and also all the BBX traffic.
Primary “A” and Redundant “B” Reference Distribution
Module Input/Output
The Reference Distribution Module (RDM) connectors route the 3 MHz
reference signals from the CSMs to the GLI2s and all BBXs in the
backplane. The signals are used to phase lock loop all clock circuits on
the GLI2s and BBX boards to produce precise clock and signal
frequencies.
Power Input (Return A, B, and C connectors)
Provides a +27 volt or –48 volt input for use by the power supply
modules.
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