Comtech EF Data SDM-650B Installation And Operation Manual page 52

Configuration
Loop timing is supported by the selection of jumper JP10. When in the ON position, the
transmit clock (ST) is replaced by the clock recovered from the satellite (RT). Active
loop timing is indicated by a yellow light on the front edge of the card. The JP10 REM
setting is for future options.
Three fault outputs are provided on dry contact FORM C relays:
•
•
•
The faults are available on the fault connector on the modem rear panel. Generation of
these fault conditions is described in Chapter 4. Fault indicators are also provided on
TTL open collector drivers on the RS-422 or MIL-STD-188-114 connector.
The TTL MOD fault indicates a Modulator fault or Common Equipment fault.
The TTL DEMOD fault indicates a Demodulator or Common Equipment fault.
The PCB for the RS-422/MIL-STD-188-114 interface is used for a number of different
interface types. The differences are jumper settings on the board, and hardware
configuration. Different parts will be installed for the various configurations. Changing to
a different interface can be done by replacing the board.
Table 3-1 describes the jumper settings for a Rev. E board.
3–10
Common Equipment
Modulator
Demodulator
SDM-650B Satellite Modem
Rev. 5