Comtech EF Data CDM-760 Installation And Operation Manual page 123

Front Panel Operation
CDM-760 Advanced High-Speed Trunking Modem
(CONFIG: INTF) (PIICX=G703)  ClkSource  ExtClock
Set the expected clock rate for the external clock source on the J8 | EXT REF BNC
connector. Use the  arrow keys to select 1 MHz, 2 MHz, 5 MHz, 10 MHz, 20 MHz,
34.368 MHz (E3), 44.736 MHz (T3), or 51.840 MHz (STS1). Press ENTER.
(CONFIG: INTF) (PIICX=G703)  ClkSource  TxClock
Lock the Tx symbol rate of the modulator to the applicable clock source. Use the 
arrow keys to select EXT CLK, RX SAT, or TX CLK. Press ENTER.
(CONFIG: INTF) (PIICX=G703)  ClkSource  RxClock
Set the clock source by which Rx data is clocked out of the G.703 interface to the
external baseband equipment. Use the  arrow keys to select RX SAT, INT CLK, TX
CLK, or EXT CLK. Press ENTER.
(CONFIG: INTF) (PIICX=G703)  Mask
Mask: TxPll:Fault
InpSigLoss:Alarm
Mask: ExtClkAct:Fault
ExtClkInRange:Alarm
Mask: RxPLL:Fault
These menus set how the modem reports interface alarm or fault states. Use the  
arrow keys to select TxPll, InpSigLoss, or more... to go to the next screens. There, use
the   arrow keys to select ExtClkAct, ExtClkInRange, RxPll, RxOF, or RxUF. Press
ENTER. Note the following:
Selection (Alarm)
TxPLL
InpSigLoss
ExtClkAct
Comtech EF Data strongly suggests that you select TX CLK, unless a high-
stability EXT CLK is present and timing of the network requires all devices to
be locked to the EXT CLK.
Comtech EF Data strongly suggests that you select RX SAT, unless a high-
stability EXT CLK is present and timing of the network requires all devices to
be locked to the EXT CLK.
RxOF:Fault
RxUF:Alarm
Description
The Tx Clock PLL is high or low, meaning that the Tx Clock Source is significantly
different than the rate of the transmitted data.
Input Signal Loss means that the PIIC G.703 interface TX-IN connector finds no
traffic.
External Clock Activity means that the External Clock is selected by either the
TxClock or RxClock, but no clock is present on J8 | EXT REF.
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Revision 4
MN-CDM760