GE Security MC100FX-TX-PoE User Manual page 13

Chapter 1: Introduction
Note: Units are shipped with the LFP function disabled (OFF).
Link Loss Return (LLR)
The fiber ports of MC100FX-TX-PoE have been designed with an LLR function
for troubleshooting a remote connection. LLR works in conjunction with LLCF.
When the LFP function is enabled, the port's transmitter shuts down when its
receiver fails to detect a valid receive link. LLR should only be enabled on one
end of the link and is typically enabled on either end of the unmanaged or
remote device.
The diagram below shows a typical network configuration with good link
status using MC100FX-TX-PoE for remote connectivity. Note that LLR and
LLCF are enabled as indicated in the diagram.
Figure 6: Good Link Status
Management Switch/Hub Media Media Switch/Hub Station
Station w/SNM P Converter Converter
LFP ON LFP ON
Fiber
Cable
LED lit = established link LED unlit = no link
If one of the optical conductors is bad (as shown in the diagram box below),
the converter with the LLR function enabled will return a no-link condition to
its link partner. The no-link condition is also carried forward to the switch or
hub where the trap was generated to the management station. The
administrator can then determine the source of the loss.
MC100FX-TX-PoE Media Converter User Manual 7