Black Box LHC5133A-R3, LHC5135A About Link Integrity, What Is FX LinkLoss?, What Is TX LinkLoss?

About FiberAlert and LinkLoss

The Compact Media Converter comes with the following troubleshooting fea- tures:

•FX LinkLoss (LinkLoss over a Fiber cable)

•TX LinkLoss (LinkLoss over a Twisted Pair cable)

•FiberAlert (including Pulsing FiberAlert)

LinkLoss and FiberAlert are advanced troubleshooting features that can help locate "silent failures" on a network. Users should understand how FiberAlert and LinkLoss work, and how they will act in a network environment, before attempt- ing to install the Compact Media Converter.

NOTE

Without understanding LinkLoss and FiberAlert, the 100 Mbps Compact Media Converter could appear flawed or even malfunctioning.

About Link Integrity

During normal operation, link integrity pulses are transmitted by all point-to- point Ethernet devices. When a Compact Media Converter receives valid link puls- es, it knows that the device to which it is connected is functioning, and that the cop- per or fiber cable coming from that device is intact. The appropriate “LINK” LED is lit to indicate this. The Compact 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. FiberAlert and LinkLoss allow this information to be obtained from the fiber, even when physical access to a remote device (and its link integrity LED) is not available.

What Is FX LinkLoss?

FX LinkLoss is a troubleshooting feature that allows users to detect failures over the fiber connection. When a fault occurs on the fiber segment of a conversion, FX LinkLoss detects the fault and passes this information to the twisted pair segment. If a Compact Media Converter is not receiving a fiber link, FX LinkLoss disables the transmitter on the Compact Media Converter 's twisted pair port. This results in a loss of link on the device connected to the twisted pair port.

What Is TX LinkLoss?

TX LinkLoss is a troubleshooting feature that allows users to detect failures over the twisted-pair connection. 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 Compact Media Converter is not receiving a twisted pair link, TX LinkLoss disables the transmitter on the media converter's fiber port. This results in a loss of link on the device connected to the fiber port.

What is FiberAlert?

FiberAlert is a troubleshooting feature that minimizes the problems associ- ated with the loss of one strand of fiber. If a strand is unavailable, the Compact Media Converter notes the lost link and will stop transmitting data and the link signal until a signal or link pulse is received. The result is that the link LED on BOTH sides of the fiber connection will go out indicating a fault somewhere in the fiber loop. Using

FiberAlert, a local site administrator is notified of a fault and can quick- ly determine the location of a cable fault.

Using FiberAlert and LinkLoss

The following table provides an overview of the troubleshooting features, their functionality and the recommended settings for a pair of media convert- ers in a typical central/main site to remote site application:

	LinkLoss/FiberAlert Comparison Table
Feature		Fault Location	Disabled LEDs	Enable At
FX LinkLoss		Fiber	Twisted Pair	Main Site Only
TX LinkLoss		Twisted Pair	Fiber	Remote Site Only
FiberAlert		Fiber	Fiber	Remote Site Only

NOTE

FiberAlert is not available/applicable on single-strand fiber versions of Compact Media Converter.

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