Comtech EF Data SDM-300A - Manual (Page 89)

SDM-300A Satellite Modem Revision 6
External Connections MN/SDM300A.IOM
4–11
Notes:
1. IDR configuration connector pinouts:
a. Backward alarm relay contacts are named for normal no fault conditions
(BWOx-C connected to BWOx-NC if no fault).
b. Backward alarm inputs should be grounded or pulled logic low to clear the
alarm.
c. Signals MF, DF, and DMA are open-collector, high-impedance (if faulted). A
backup protection switch uses MF and DF if the modem is used in a redundant
system.
d. Relay contacts DF-C and DF-NO are named for faulted condition (DF-C
connected to DF-NO, unless demodulator [Demod] fault).
2. D&I/ASYNC interface connector pinouts:
a. With regard to alarm relay contacts, COMM is connected to NO when there is
no fault. COMM is connected to NC in a faulted condition.
b. Signals MF, DF, and DMA are open-collector, high-impedance (if faulted). A
backup protection switch uses MF and DF if the modem is used in a redundant
system.
3. The breakout panel provides the external connections between the modem and the
terrestrial equipment when the modem has a 50-pin connection.