User's Manual

Download the BTS68P09258A31–A
Oct 2003
1X SCt 4812T BTS Optimization/ATP
3-41
Enable CSMs
NOTE
– 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.
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 LFR, 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.
Table 3-16: Enable CSMs
n Step Action
1 Click on the target CSM (CSM–2 first, if equipped with two CSMs).
2 From the Device pull down, select Enable.
– A status report is displayed confirming change in the device(s) status.
– Click OK to close the status report window.
NOTE
– The board in slot CSM 1 interfaces with the GPS receiver. The enable sequence for this board can
take up to one hour (see below).
– FAIL may be shown in the status report table for a slot CSM 1 enable action. If
Waiting For Phase
Lock is shown in the Description field, the CSM changes to the Enabled state after phase lock is
achieved.
* IMPORTANT
– The GPS satellite system satellites are not in a geosynchronous orbit and are maintained and
operated by the United States Department of Defense (D.O.D.). The D.O.D. periodically alters
satellite orbits; therefore, satellite trajectories are subject to change. A GPS receiver that is INS
contains an “almanac” that is updated periodically to take these changes into account.
– If a GPS receiver has not been updated for a number of weeks, it may take up to an hour for the
GPS receiver “almanac” to be updated.
– Once updated, the GPS receiver must track at least four satellites and obtain (hold) a 3–D position
fix for a minimum of 45 seconds before the CSM will come in service. (In some cases, the GPS
receiver needs to track only one satellite, depending on accuracy mode set during the data load).
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