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LinkLoss, FiberAlert and Link Fault Pass-Through
Gigabit Compact Media Converter includes the troubleshooting features FiberAlert, TXLL,
FXLL and LFPT that help locate
silent failures
on a network. Before attempting to install
the module(s), understand how these features work and react to specific network
configurations.
WARNING
Installing modules without understanding the effects of LinkLoss and FiberAlert can
cause functioning units to appear flawed or even non functional.
Link Integrity
During normal operation, link integrity pulses are transmitted by all point-to-point
Ethernet devices. When a Black Box media converter receives valid link pulses, it knows
that the device to which it is connected is up and sending pulses, and that the copper or
fiber cable coming from that device is intact. The appropriate “LNK” (link) LED is lit to
indicate this.
The Black Box media converter also sends out link pulses from its copper and fiber
transmitters, but normally has no way of knowing whether the cable to the other device is
intact and the link pulses are reaching the other end. The combination of FiberAlert and
LinkLoss allows this information to be obtained, even when physical access to a remote
device (and its link integrity LED) is not available.
FX LinkLoss (FXLL)
FX LinkLoss is a troubleshooting feature. When a fault occurs on the fiber segment of a
conversation, FX LinkLoss detects the fault and passes this information to the twisted pair
segment. If a media converter is not receiving a fiber link, FX LinkLoss disables the
transmitter on the media converter’s twisted pair port. This results in a loss of link on the
device connected to the twisted pair port.
TX LinkLoss
TX LinkLoss is a troubleshooting feature. When a fault occurs on the twisted pair segment
of a conversion, TX LinkLoss detects the fault and passes this information to the fiber
segment. If a media converter is not receiving a twisted pair link, TX LinkLoss disables the
transmitter n the media converter's fiber port. This results in a loss of link on the device
connected to the fiber port.