User Manual

MDR2400/5800-SR, Orion2410/5810-SRi and Orion 5825-SR
862-01881 Issue 12c Page 124
the patch panel are exactly the same as that of the MDR and Orion Digital Indoor Units
respectively.
J.2.2.2 Auxiliary port communication
The two Digital Indoor Units on each side of the radio link share status information
through the two relay outputs and OPTO inputs on the Auxiliary (AUX) port of each
Digital Indoor Unit. Information shared by each of these:
• Indication if the Digital Indoor Unit is currently driving the tributary channels on
the user network
• The current Frame Lock status detected by the Digital Indoor Unit for the radio
link it is using
J.3 System functional description
Each Digital Indoor Unit taking part in a protected radio link continuously monitors the
PER of the radio link it is receiving tributary data over. If the PER for the link increases
above the Sever Error Margin for more than 10 consecutive seconds, the Digital
Indoor Unit will request the second Digital Indoor Unit to take over the driving of the
tributary channels if the second Digital Indoor Unit sees a frame lock.
Once the second Digital Indoor Unit has started driving the tributary channels, the first
Digital Indoor Unit becomes the redundant link.
The flow diagram for the algorithm that governs the protection switch-over process in
each Digital Indoor Unit is illustrated in Figure 11.
Is IU driving the
Tribs
PER >
Threshold
YES
YES
Timer >= 10sec
Redundant IU
has frame lock
YES
Start Driving Tribs
& Signal
Redundant IU
Is Redundant
IU driving Tribs
IU has frame
lock
Reset Timer
Stop Driving Tribs
& Signal
Redundant IU
NO
NO
YES
YES
NO NO
YES
Reset
Figure 11: Redundant system switch-over algorithm.