Specifications

X723-300151 5-21 Issue 2
5.4.4 Sync Source
A menu command allows the operator to modify the sync source and sync
priority selections for the configuration of the multiplexer. Up to four sync
source selections can be entered after which the list will be terminated
with free run.
Modify Format
Each sync source selected will be displayed in turn until freerun is
reached. The last sync source in any selection will always be free run.
(CCEM) Port | sYnc | Alarms | Cross connect >Y
failure recovery mode 1 (manual), 2 (automatic)
mode = 2 >
automatic recovery delay period 1-60 (seconds)
hold = 10 >
source selections:
1 (port)
2 (8k1)
3 (8k2)
4 (free run)
priority 1 = 4 (free run) >1
port (1,2,3,4),card,option (1=line1 2=line2 3=clk)>3, C, 2
priority 2 = 4 (free run) >1
port (1,2,3,4),card,option (1=line1 2=line2 3=clk)>2, A, 1
priority 3 = 4 (free run) >
(CCEM) Port | sYnc | Alarms | Cross connect
*
>
If manual clock recovery is selected, the multiplexer will automatically
fallback to a lower priority clock, but will only re-select a higher priority
clock by manually re-running the current configuration. If automatic
clock recovery is selected the sync source will automatically revert to the
highest good source available. The switch back may be delayed for up to
60 secs from when the good clock is first detected.
The Series 3000 can be synchronised to a 2MHz or two 8kHz, known as
8k1 and 8k2, internal clock busses generated by certain channel cards.
Access to the 2MHz clock bus is fully controlled by the system controller.
However, access to the 8kHz busses are not. This is controlled by link
selection on the channel cards. Care should be taken to ensure only one
channel card is connected to each of the 8kHz clock busses at any one
time.