Comtech EF Data CDM-760, Installation And Operation Manual

Page: 124 / 441

Front Panel Operation Revision 4
CDM-760 Advanced High-Speed Trunking Modem MN-CDM760
6–35
Selection (Alarm) Description
ExtClkInRange
External Clock In Range means that the External Clock is set by the TxClock or
RxClock, but the rate of the clock on J8 | EXT REF does not agree with the rate
expected by the modem.
RxPLL
The Rx Clock PLL is railed high or low, meaning that the Rx Clock Source is
significantly different than the rate of incoming data.
RxOF
Rx Overflow means that the demodulator traffic is too fast for the RxClock clock
setting. This causes the buffer to overflow and to re-center, losing data in the
process.
RxUF
Rx Underflow means that the demodulator traffic is too slow for the clock RxClock
setting. This causes the buffer to underflow and to re-center, losing data in the
process.
If ExtClkAct IS NOT in an Alarm or Fault condition but the ExtClkInRange IS in
Alarm or Fault condition, this means that the clock source rate and the
modem’s programmed External Clock rate are different.
Use the

arrow keys to set the report state for each selection as Alarm , Fault ,
Mask , or Fault-Tx On . (The RxPll , RxOF , and RxUF selections provide only Alarm , Fault ,
and Mask .) Press ENTER . Note the following:
Mask State
Front Panel LED
‘UNIT STATUS’
Color
Fault State
Causes
Redundancy
Switch
Mutes
Tx Carrier
Front Panel VFD
Visible Location
Alarm Amber None No No Monitor: Live Alarms menu
Fault Red
J1 Alarm
Connector
Yes Yes Monitor: Stored-Events Log
Mask None None No No
None: A masked event is not
logged and is not seen in
any menu.
Fault-Tx On Red
J1 Alarm
Connector
Yes No Monitor: Stored-Events Log
(CONFIG: INTF) (PIICX=G703)

BufSize (Rx Buffer Size)
Rx Buffer Size: 02.0 ms
(

)
Use the

arrow keys to change the Rx Buffer Size time value. Press ENTER . Valid settings are:
Range
Step Size
Minimum Maximum
2 ms 75 ms 0.5 ms
(CONFIG: INTF) (PIICX=G703)

Center (Rx Buffer Re-Center)
PIICX: Type:E3 ClkSource Mask
BufSize:32.0ms Center:No Fill=50% (

)
The Fill Status is a
read-only
status of buffer depth, reported as a percentage: