Comtech EF Data SMS-758 - Manual (Page 95)

SMS-758 Modem Protection Switch Theory of Operation
MN/SMS758 Rev. 3 4–35
4.6.6.2 Operation
When configuring modem setup on the front panel, it is recommended to select #9 - IDR
2:N for the interface selection.
Note: The 1877 and 1879 interface will not work when #5 - IDR is selected in the
modem setup configuration. This interface cannot be used in conjunction with any
interface switch modules that only support 1 backup. These include the AS/0895 and
AS/0896 IDR modules. Check the rear of the switch and verify that none of the interface
switch modules are the AS/0895 or AS/0896 modules.
4.6.6.3 Connector Pinouts
The 2:N IDR interface uses a 50-pin female D connector.
Screw locks provide mechanical security of the mating connector.
Signal Function Name Pin #
Ground - 1, 2
Send Data SD-A
SD-B 34
18
Receive Data RD-A
RD-B 36
20
Reference Clock EXC-A
EXC-B 35
19
8 KBPS TX Data TXD-A
TXD-B 37
38
8 KHz TX Clock Out TXC-A
TXC-B 21
22
1 KHz TX Octet In TXO-A
TXO-B 4
5
8 KBPS RX Data RXD-A
RXD-B 39
40
8 KHz RX Clock Out RXC-A
RXC-B 23
24
1 KHz RX Octet Out RXO-A
RXO-B 6
7
Backward Alarm 1 Out BWO1-C
BWO1-NC
BWO1-NO 8
25
41
Backward Alarm 2 Out BWO2-C
BWO2-NC
BWO2-NO 9
26
42
Backward Alarm 3 Out BWO3-C
BWO3-NC
BWO3-NO 10
27
43
Backward Alarm 4 Out BWO4-C
BWO4-NC
BWO4-NO 11
28
44
Backward Alarm 1 In BWI1 12
Backward Alarm 2 In BWI2 13