Comtech EF Data SMS-758 User Manual
Page 101
SMS-758 Modem Protection Switch
Theory of Operation
MN/SMS758 Rev. 3
4–41
Primary Alarm Out
PRI_COM
PRI_NO
PRI_NC
10
43
27
Secondary Alarm Out
SEC_COM
SEC_CO
SEC_NO
11
44
28
Modulator Fault
MF
49
Demodulator Fault
DF
33
TRANSMIT DATA
TRANSMIT ESC
RECEIVE DATA
RECEIVE EXTERNAL
REFERENCE CLOCK
RECEIVE ESC
TX S/B
TX
TX
PRIME C/U
DATA I/O
RX
TERRESTRIAL
DATA I/O
RX
B/U #1 AND B/U #2
DATA PATH
SELECTION
RX S/B
RX
NOTE: THE RELAYS ARE SHOWN IN THE NON-ENERGIZED
POSITION CONNECTING THE TERRESTRIAL DATA AND
PRIME MODEM CONNECTORS TOGETHER. STANDBY (S/B)
SIGNALS ARE ROUTED TO THE OFFLINE BACKUP MODEM.
TRANSMIT DATA
RECEIVE DATA
RECEIVE ESC
TRANSMIT ESC
RECEIVE EXTERNAL
REFERENCE CLOCK
MOD AND DEMOD FAULTS
DATA SW ITCH
MOTHERBOARD
INSTRUCTION
DECODER
TX RELAYS
RX RELAYS
FAULTS
TRANSMIT DATA
TRANSMIT ESC
RECEIVE DATA
RECEIVE ESC
RECEIVE EXTERNAL
REFERENCE CLOCK
Figure 4-14. Prime 2:N IBS Interface Switch (1695)