Nortel Networks Video Gaming Accessories 553-3001-211 Manual De Usuario

 NT5D97 Dual-port DTI2/PRI2 card

system switches to the back-up clock controller, without affecting which 
reference clock is being tracked.

A reference-clock error occurs when there is a problem with the clock driver 
or with the reference clock at the far end. If the clock controller detects a 
reference-clock error, the reference clocks are switched.

A command for automatic clock recovery can be selected in LD 60 with the 
command EREF.

A DDP2 loop is disabled when it enters a local-alarm condition. If the local 
alarm is cleared, the loop is enabled automatically. When the loop is enabled, 
clock tracking is restored in the following conditions:

•

If the loop is assigned as the primary reference clock but the clock 
controller is tracking on the secondary reference or in free-run mode, it 
is restored to tracking on primary.

•

If the loop is assigned as the secondary reference clock but the clock 
controller is in free-run mode, it is restored to tracking on secondary.

•

If the clock check indicates the switch is in free-run mode:

— Tracking is restored to the primary reference clock if defined.

— If the primary reference is disabled or in local alarm, tracking is 

restored to the secondary reference clock if defined.

Note: If the system is put into free-run mode by the craftsperson, it 
resumes tracking on a reference clock unless the clock-switching option 
is disabled (LD 60, command MREF), or the reference clock is 
“undefined” in the database.