The Redundancy Controller (Second box from the top) monitors a number of other boxes. In this case frequency converters. The rack shown in the picture below is a 1 for 8 redundant system. There are 8 active frequency converters and one back up frequency converter. If one of the 8 converters breaks down then the redundancy controller switches in the back up unit. The switching process consists of setting the backup unit to the correct parameters to match the faulty unit (Frequency, power and so on) and then controlling RF coaxial switches to route the signals through the backup unit.
The second box is the redundancy controller.
Third box is the backup frequency converter
Then 8 on line converters.
These frequency converters are used in large satellite earth stations to send information up to the satellite. They convert the output of the modem to the RF frequency used on the satellite. (C, ku or Ka band)
Blue box - Ethernet switch - Ethernet cables go to all boxes to permit their status to be monitored individually.
Gold box - Redundancy Controller
To the right we have the coaxial switch modules. Each switch module is connected to a frequency converter (grey wire for control, black wire for the IF and blue wire for RF.)
By keeping the switch modules as separate modules daisy chained together, we can have any number of RF units. (This system is 1:8). In addition, should a RF switch fail, the module can be replaced without taking the whole rack off line.
The RF switch modules are used to configure the frequency converters so when a converter is replaces, the technician simply presses a button and a previously stored configuration is loaded into the converter and it is ready to go.
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