User Manual

CSM System Time – GPS & HSO Verification

July 1999

3-29

SC 4812ET BTS Optimization/ATP – CDMA LMF

PRELIMINARY 2

CSM & LFR Background

The primary function of the Clock Synchronization Manager (CSM)

boards (1 & 2) is to maintain CDMA System Time. The master GLI can

request and distribute system time to the appropriate modules within a

C–CCP shelf. The redundant GLI (slave) obtains system time from the

master GLI over the LAN. All boards are mounted in the C–CCP shelf.

Each CSM board features an ovenized, crystal oscillator that provides

19.6608 MHz clock, even second tick reference, and 3 MHz sinewave

reference, referenced to the selected synchronization source (GPS,

LORAN–C Frequency Receiver (LFR), or High Stability Oscillator

(HSO), T1 Span, or external reference oscillator sources). The 3 MHz

signals are also routed to the RDM EXP 1A & 1B connectors on the top

interconnect panel for distribution to co–located frames at the site.

Fault management has the capability of switching between the CSM 1

and 2 boards in the event of a GPS receiver failure on CSM 1 or a

reference oscillator failure on either CSM board. During normal

operation, the CSM 1 board oscillator output is selected as the source.

The source selection can also be overridden via the LMF or by the GLI

card.

Front Panel LEDs

 Steady Green – Master CSM locked to GPS or LFR (INS).

 Rapidly Flashing Green – Standby CSM locked to GPS or LFR

(Stby).

 Flashing Green / Rapidly Flashing Red – CSM OOS–RAM

attempting to lock on GPS signal.

 Rapidly Flashing Green / Red – Alarm condition exists. Trouble

Notifications (TNs) are currently being reported to the GLI.