User Manual

Download the BTS – continued
3-38 1X SC4812T–MC BTS Optimization/ATP 5/21/04
DRAFT
Table 3-15: Select CSM Clock Source
n ActionStep
3 Select the applicable clock source in the Clock Reference Source
pick lists. Uncheck the related check boxes for Clock Reference
Sources 2 and 3 if the displayed pick list items should not be used.
4 Click on the OK button – a status report window displays the results
of the selection action.
5 Click on the OK button to close the status report window.
For non–RGPS sites only, verify the CSM configured with
the GPS receiver “daughter board” is installed in the
CSM–1 slot before continuing.
NOTE
Enable CSMs
CSMs are code loaded at the factory. This data is retained
in EEPROM. The download code procedure is required in
the event it becomes necessary to code load CSMs with
updated software versions. Use the status function to
determine the current code load versions.
The CSM(s) to be enabled must have been downloaded
with code (Yellow, OOS–RAM) and data.
NOTE
Each BTS CSM system features two CSM boards per site. In a typical
operation, the primary CSM locks its Digital Phase Locked Loop
(DPLL) circuits to GPS signals. These signals are generated by either an
on–board GPS module (RF–GPS) or a remote GPS receiver (R–GPS).
The CSM2 card is required when using the R–GPS. The GPS receiver
(mounted on CSM–1) is the primary timing reference and synchronizes
the entire cellular system. CSM–2 provides redundancy but does not
have a GPS receiver.
The BTS may be equipped with a remote GPS, LORAN–C, HSO 10
MHz Rubidium source, or HSOX for expansion frames, which the CSM
can use as a secondary timing reference. In all cases, the CSM monitors
and determines what reference to use at a given time.
Follow the procedure in Table 3-16 to enable the CSMs.
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