Unit installation

Theory of Operation RSU-503 Redundancy Switch Unit
3–4 Rev. 8
Downlink
B4 B5 B6 B7 WR8000, B2 WR8000, B5
IF_A RF_A IF_B RF_B 1= A ON LINE
0 = B ON LINE
1 = OKAY
0 = AMBIGUITY FAULT
0000 1 0
0001 1 0
0010 1 0
0 0 1 1 1 1 - Valid state, A online
0100 0 0
0101 0 0
0110 0 0
0111 0 0
1000 1 0
1001 1 0
1010 1 0
1011 1 0
1 1 0 0 0 1 - Valid state, B online
1101 0 0
1110 0 0
1111 0 0
3.4.3 Auto/Manual Modes
In Auto mode, switch-over can only occur as a result of a fault, as listed in the following
table:
RD9001
B0 B1
UL FLT A UL FLT B Fault Description
0 0 No faults.
0 1 Fault on B uplink, switch to uplink A, WR8001 B0.
1 0 Fault on A uplink, switch to uplink B, WR8001 B1.
1 1 Fault on both, do nothing. Monitor, and switch to the first
unit to remote the fault.
B2 B3
DL FLT A DL FLT B Fault Description
0 0 No faults.
0 1 Fault on B downlink, switch to downlink A, WR8001 B2.
1 0 Fault on A downlink, switch to downlink B, WR8001 B3.
1 1 Fault on both, do nothing. Monitor, and switch to the first
unit to remote the fault.
In Manual mode, the switch initiates the online pulses from only two sources:
• Request from the MTI
• Onboard push-button switches
In normal service with the cover secured, switch-over can occur only from an MTI
request.