User Manual
C–CCP Backplane Troubleshooting
July 1999
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SC 4812ET BTS Optimization/ATP – CDMA LMF
PRELIMINARY 2
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 will
allow the Cellular Field Engineer (CFE) to:
Determine which connector(s) is associated with a specific problem
type.
Allow the isolation of problems to a specific cable or connector.
Primary “A” and Redundant “B” ISB (Inter Shelf Bus)
connectors
The 40 pin ISB connectors provide an interface bus from the master
GLI2 to all other GLI2s in the modem frame. Its basic function is to
provide clock synchronization from the master GLI2 to all other GLI2s
in the frame.
The ISB is also provides the following functions:
span line grooming when a single span is used for multiple cages.
provide MMI connection to/from the master GLI2 to cell site modem.
provide 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 BBX2 traffic.
Primary “A” and Redundant “B” Reference Distribution
Module (RDM) Input/Output
These connectors route the 3 MHz reference signals from the CSMs to
the GLI2s and all BBX2s in the backplane. The signals are used to phase
lock loop all clock circuits on the GLI2’s and BBX2 boards to produce
precise clock and signal frequencies.
Power Input (Return A, B, and C connectors)
Provides a 27 volt input for use by the power supply modules.
Power Supply Module Interface
Each power supply module has a series of three different connectors to
provide the needed inputs/outputs to the C–CCP backplane. These
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