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MBT-4000B Multi-Band Transceiver System
Appendix B
Figure B-1 illustrates a typical Dual-Base (Chain) Redundancy configuration. The two MBT-4000B
base units cooperate in monitoring the health of the two BUCs, two external amplifiers, two
Low-Noise Block Down Converters (LNBs), and each other. In case of a fault on an online
BUC/amplifier or LNB, the MBT-4000B base containing the corresponding standby chain will
automatically switch over to the standby chain in accordance with the following rules:
1. In dual-base (chain) redundancy operation, the redundancy is 'slot' based. The
corresponding pairs reside in the same 'slot' of the opposite MBT-4000B base, the pair
of BUCs connected to the "J3 | UNIT 1 COMM" (Slot 1) connector on each base form a
redundant pair. The LNBs connected to the "J12 | L-BAND IN" connector on each base
form the other redundant pair.
2. The corresponding BUCs in a pair must be of the same band type.
3. The Redundancy Interlink Cable (CEFD P/N CA/WR11224-1 or equivalent) must be
installed.
4. Base unit identification (MBT1 or MBT2) is driven by the redundancy interlink cable.
Hard-wired connections within the cable designate one MBT-4000B base as MBT1 and
the other as MBT2. The cable is labeled accordingly.
5. The RF and IF switches connected to MBT1 correspond to the redundant pair of BUCs
installed on the "J3 | UNIT 1 COMM" (Slot 1) connector.
6. The RF and IF switches connected to MBT2 correspond to the redundant pair of LNBs
installed on the "J12 | L-BAND IN" connectors.
7. When a BUC or LNB attached to MBT1 is online, the corresponding RF and IF switches
will be switched to Position "A". When a BUC or LNB attached to MBT2 is online, the
corresponding switches will be switched to Position "B".
For a switchover to occur:
1. Both MBT-4000B base units must be set to Redundancy Mode 2. The RED=2 remote
command must have been received by each base.
2. Both chains must be set to Automatic Mode. For example, if the redundant pair is on
Slot 2 of the bases, the RAM=21 remote command must have been received by each
base.
3. The corresponding standby chain must not be in faulted state.
B–3
Revision 1
MN/MBT4000B.IOM
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