B&B Electronics 855-11844--51 - Manual - Manual (Page 6)

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** 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 an B&B Electronics 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 B&B Electronics 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.
LinkLoss, FiberAlert and Link Fault Pass-Through
McBasic-Gigabit 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.
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 (TXLL)
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 on the media converter's fiber port. The result is in a
loss of the link on the device connected to the fiber port.
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Troubleshooting
 During installation, first test the fiber and twisted pair connections with all
Troubleshooting features disabled, then enable these features, if desired, just
before final installation. This will reduce the features’ interference with testing.
If using a high powered device (which is designed for long distance installations) for a
short distance installation, the fiber transmitters may overdrive the receivers and
cause data loss. If this is the case, an optical attenuator may need to be added to the
connection.
For fiber specifications, visit the B&B Electronics Web site at:
www.bb-elec.com or
contact B&B Electronics for more information.