Comtech EF Data SMS-758 - Manual (Page 75)

SMS-758 Modem Protection Switch Theory of Operation
MN/SMS758 Rev. 3 4–15
DATA PATH
SELECTION
TRANSMIT CLOCK
TRANSMIT DATA
RECEIVE DATA
RECEIVE CLOCK
RECEIVE EXTERNAL REFERENCE CLOCK
MOD AND DEMOD FAULTS
DECODER
INSTRUCTION
BACKUP
DATA I/O
DATA SWITCH
MOTHERBOARD
MOD RELAYS
DEMOD RELAYS
Figure 4-3. Backup RS-422/449 and MIL-STD-188-114/RS-449 Interface Switch