Product specifications

B–1
Appendix B. REDUNDANT
SYSTEM OPERATION
B.1 Introduction to Redundancy Operation
The Comtech EF Data UT-4500-A Series Upconverters are configured for redundant system
operation using distributed protection switching in an active "Daisy Chain" configuration.
Comtech EF Data's proprietary "Daisy Chain" configuration distributes the upconverter
protection switching functions in the upconverters. This provides a system capability to backup
from 1 to 12 online upconverters.
A High Speed Bus (HSB) provides the communications interface between the backup and online
upconverters to detect faults and reconfigure the subsystem to replace the failed upconverter.
When a faulted upconverter is removed from active operation, it is detached from the active
upconverter chain by separating the upconverter from its switch module, leaving the active online
upconverter chain intact through the switch module. The chain can be extended without affecting
the online upconverter operation.
The active "chained" upconverters in a redundancy subsystem can also be indirectly controlled
through the backup upconverter using the remote serial communication link – this capability is
discussed in Appendix A. REMOTE CONTROL.
B.2 Backup Upconverter
The "Daisy Chain" terminates in the backup upconverter. The backup upconverter has a
microprocessor, which performs fault detection, self-reconfiguration and the logical switching
functions. If the backup upconverter does not have a fault, it will assume the frequency and
attenuation of the faulted upconverter and compensate for the chain losses. This capability is
accomplished through the operation of the HSB and the online upconverter detachable switch
modules.
B.2.1 High Speed Bus (HSB)
In the "Daisy Chain" configuration, the backup upconverter communicates with the online units
through the HSB. The backup upconverter is able to detect faults and reconfigure itself to replace