Plessey MDR2400-SR, User Manual, Page: 124 / 131

MDR2400-SR, MDR5800-SR and Orion 5825-SR
Issue 10
Page 124
Table 13: Protection Kit connector interfaces.
Description Connector Impedance
Orion Protection Panel
Payload Network Interface 2xDB-25 or 8xRJ-48 110 ohm
Indoor Unit Interface 2x2xDB-25 110 ohm
Orion Protection Panel
Payload Network Interface DB-25 or 4xRJ-48 110 ohm
Indoor Unit Interface 2xDB-25 110 ohm
The cables required to connect the Patch Panel to the two Indoor Units are provided
with the Patch Panel. The DB-25 pinouts used for each DB-25 connector on the patch
panel are exactly the same as that of the MDR and Orion Indoor Units respectively.
Auxiliary port communication
The two 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 Indoor Unit.
Information shared by each of these:
•
Indication if the Indoor Unit is currently driving the tributary channels on the user
network
•
The current Frame Lock status detected by the Indoor Unit for the radio link it is
using
System functional description
Each 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 Indoor Unit will
request the second Indoor Unit to take over the driving of the tributary channels if the
second Indoor Unit sees a frame lock.
Once the second Indoor Unit has started driving the tributary channels, the first Indoor
Unit becomes the redundant link.
The flow diagram for the algorithm that governs the protection switch-over process in
each Indoor Unit is illustrated in Figure 11.