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MBT-4000 Multi-Band Transceiver System
Redundancy Configuration / Operation
6. The RF and IF switches connected to MBT-B correspond to the redundant pair of BxCs
installed on J6 UNIT 2 COMM (Slot 2).
7. When a BxC attached to MBT-A is online, the corresponding RF and IF switches will be
switched to position A. When a BxC attached to MBT-B is online, the corresponding
switches will be switched to position B.
For a switchover to occur:
1. Both MBT-4000 base units must be set to redundancy mode 2, the RED=2 command
must have been received by each base.
2. Both BxCs must be set to automatic mode. For example, if the redundant pair is on Slot 2
of the bases, the command RAM=21 must have been received by each base.
3. The corresponding standby BxC must not be in faulted state.
C.4
External Fault Monitoring
Each MBT-4000 base includes two logic inputs, one per AUX COMM connector, that may be
connected to contact closure fault indications of external equipment (usually an SSPA or LNA).
Thus, external equipment failure may participate in overall fault indication and redundant
switchover operation according to the following rules:
1. An open connection (or 2.7 V min) indicates a fault condition exists.
2. A closed connection (or 0.7 V max) indicates no fault condition exists.
3. Maximum voltage range on fault logic inputs is –12V to +12V.
4. The fault inputs correspond to a slot, the fault input of AUX COM 2 corresponds to the
BxC installed as UNIT 2. The fault input of AUX COM 1 corresponds to the BxC
installed as UNIT 1.
5. To enable fault input checking the EFI=nm command is usedwnput parameter 'n' can
equal 1for AUX COM 1 input, or 2 for AUX COMM 2 input. The mode parameter 'm'
can equal 0 for disabled, or 1 for enabled. Each input must be enabled individually.
C.5
LNA Power Supply Current Monitoring
The MBT-4000 base and BDC-4000 are capable of supplying power to external LNAs. The
MBT-4000 base supplies the power from a pin in the AUX COMM connectors; the BDC-4000
supplies the power over the center conductor of the coaxial cable. These power supplies feature
current monitoring with programmable failure limits. Overcurrent and undercurrent failures can
participate in overall fault indication and redundant switchover criteria.
The following commands and rules configure operation of this feature:
1. The power supplies are +12.6V with a 350 mA current limit.
2. No more than two of the four possible supplies should be enabled simultaneously.
3. An individual supply is enabled by issuing the 'LCS=sm' command as follows:
a. 's' is the source. Valid values are 1 or 2 where: 1=AUX COMM 1 supply and
2=AUX COMM 2 supply. The BDC-4000 only has a single current source, so 's'
must be set to 1 on a BDC-4000.
C–3
Revision 4
MN/MBT4000.IOM
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