Comtech EF Data SMS-758 - Manual (Page 87)

SMS-758 Modem Protection Switch Theory of Operation
MN/SMS758 Rev. 3 4–27
4.6.4.1 Specification
Circuits Supported SD, RD, MC.
Switching Format Modulator and demodulator signals switched individually
with dry contacts.
Contact Arrangement Modulator signals: 2 poles.
Demodulator signals: 4 poles.
4.6.4.2 Connector Pinouts
The DS-1 and G.703 interface uses a 15-pin female D connector accessible from the
switch rear panel.
Screw locks provide mechanical security for the mating connector.
Signal Function Name Pin #
Shields - 2,4
Send Data SD-A 1
SD-B 9
Receive Data RD-A 3
RD-B 11
Master Clock MC-A 7
MC-B 8
Modulator Fault MF 14
Demodulator Fault DF 15
Note: MF and DF inputs are only on the prime and backup modem interface connectors,
not the terrestrial data connector.