SMS-758 Modem Protection Switch
Installation
MN/SMS758 Rev. 3
2–5
Table 2-1. Rear Panel Connections
Name
Ref. Desig.
Connector
Function
DATA I/O
A1 - A10
J1, J2
37-Pin D
34-Pin Block
15-Pin D
37-Pin D
50-Pin D
50-Pin D
RS-422/449 and
MIL-STD-188-114 I/O
V.35 I/O
DS-1 and G.703 I/O
DCTN I/O
IDR I/O
IBS I/O
EXTERNAL
RS485
RS232
J1
J2
9-Pin D
9-Pin D
Remote Interface
MODEM
CONTROL RS485
J3
9-Pin D
Remote Interface
ON-LINE STATUS
J4 and J5
25-Pin D
Mod and Demod Online Status
Reporting
REMOTE/FAULTS
J6
25-Pin D
Relay/Remote and Faults
DOWNLINK
INPUTS
J7 through J10,
J12 through J15
BNC
Downlink IF Inputs
BACK-UP
DEMODS
J11 through J16
BNC
Downlink Outputs to Backup
Demods
PRIME MOD
INPUTS
J18 through J25
BNC
Modulator IF Inputs
BACK-UP MOD
INPUTS
J26 and J36
BNC
Backup Mod IF Inputs
OFF-LINE IF
OUTPUTS
J17 and J27
BNC
Offline Mod IF Outputs
IF OUTPUTS
J28 through J35
BNC
IF Outputs to Uplinks
AC POWER
J37, J38
CEE22
AC Power Input
DC POWER
J37, J38
Terminal
Block
48 VDC Power Input
GROUND
J39
#10-32 Stud
Chassis Ground
Note: All unused BNC connectors must have a 75
Ω
termination.
2.4.1 Data I/O
Connect the Modem and Terrestrial Data I/O to the plug-in interface switch modules in
the lower rear section of the switch. The interface switch module slots are designated A1
through A10 (left to right, viewed from the rear). A1 through A8 are slots for prime
interface switch modules 1 through 8. A9 and A10 are backup module slots 1 and 2.
Prime interface switch modules have two connectors: J1 on the top connects to terrestrial
equipment; J2 on the bottom connects to the prime modem. (See Note below.) Backup
interface switch modules have one connector, J1, for backup modem connection. Refer
to Section 4.3 for electrical specifications, and data pin-outs.
Note: For the RS-422/449/MIL-STD-188-114 interface switch modules: J1 on the left
connects to the prime modem, and J2 on the right connects to the terrestrial equipment.
