Comtech EF Data SMS-451 - Manual (Page 50)

SMS-451 Satellite Switch Revision 0
Operation MN/SMS451.IOM
3-4
3.3.2 SMS-451A/E Demodulator Operation
To operate the switch from the front panel, REM/LOC must be set to the LOC position.
1. Manually force Demodulator “A” online by switching the demodulator switch to
the “A” position. The yellow MANUAL LED and the green ONLINE “A”
LED will light.
2. Manually force Demodulator “B” online by switching the demodulator switch to
the “B” position. The yellow MANUAL LED and the green ONLINE “B” LED
will light.
Notes:
1. The AUTO position will allow the switch to automatically backup the faulty
demodulator, which will be indicated by a red FAULT LED on the front
panel.
2. In the event that both demodulators are in fault condition, the switch will
remain on the last known operational demodulator if independent modem-
switching firmware is installed. The switch will default to “A” if dependent
modem-switching firmware is installed.
3.4 SMS-451A/E Remote Operation
Remote control operation of the switch is available only when the front panel REM/LOC
switch is in the REM position (the yellow REMOTE LED should be illuminated).
Remote status information of the online modulator and demodulator is available
regardless of the position of the REM/LOC switch.
Example: A closure between pin 15 and pin 7 on the remote interface connector is
an indication that demodulator “A” is online.
Remote control is accomplished by making an external contact closure between the
proper control pins and one of the pins that is assigned to GND.
Example: An external closure between pin 14 and pin 2 on the remote interface
connector will force demodulator “A” online.
Mode Status is an indicator of which configuration (local or remote) is selected.
Example: A closure between pin 16 and pin 18 on the remote interface connector is
an indication that the switch is in local operation.