Installing modules without understanding the effects of FiberAlert
can cause perfectly functioning units to appear flawed or even
dead!
If you are unfamiliar with FiberAlert and LinkLoss, IMC Networks
strongly encourages you to read the following information. Contact IMC
Networks technical support at (800) 624-1070 (U.S. and Canada),
+32-16-550880 (Europe) or
for more
information and assistance.
A
B O U T
L
I N K
I
N T E G R I T Y
During normal operation, link integrity pulses are transmitted by all
point-to-point Ethernet devices. When an IMC Networks media convert-
er receives valid link pulses, it knows that the device to which it is con-
nected is up and sending pulses, and that the copper or fiber cable com-
ing from that device is intact. The appropriate “LINK” LED is lit to indi-
cate this. The IMC Networks media converter also sends out link pulses
from its copper and fiber transmitters, but normally has no way of know-
ing 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.
W
H A T
I
S
F
I B E R
A
L E R T
?
FiberAlert lets you know when a fault occurs on your fiber loop by
stopping data transmissions and affecting fiber LEDs on both sides of your
network. If a media converter is not
receiving a fiber link, FiberAlert dis-
ables the media converter's fiber
transmitter, thus mirroring the link
status of the opposite end of the
fiber. Both fiber link LEDs on either
end of the link should extinguish,
alerting you to the fault. Using FiberAlert, a local site administrator is noti-
fied of a fault and can quickly determine where a cable fault is located
with-
out
hav-
ing
to go
to the remote site.
W
H A T
I
S
L
I N K
L
O S S
?
LinkLoss functions much like FiberAlert in that faults on one port are
mirrored on the other. In the case of LinkLoss, however, a fault on the
3
N O T E
FiberAlert should only be enabled on one side of a media conversion.
Enabling it on both sides would keep both transmitters off indefinitely.
fiber port is passed to
the Ethernet twisted
pair port.
If a media converter
is not receiving a fiber
link, LinkLoss disables the transmitter on the media converter's twisted
pair port. This results in a loss of link on the remote twisted pair device.
E
N A B L I N G A N D
U
S I N G
F
I B E R
A
L E R T A N D
L
I N K
L
O S S
FiberAlert and LinkLoss are configured on McBasic TP/FO by adjusting
a two-position switch on the faceplate next to the fiber connectors. The
switch for LinkLoss is labeled “LL.” The switch for FiberAlert is labeled
“FA.” Enable LinkLoss or FiberAlert by moving the corresponding switch
to the up (ON) position. Disable either (default) by moving the switch to
the down (OFF) position.
In a central site to remote site media conversion, IMC Networks recom-
mends you enable your McBasic TP/FOs’ troubleshooting features as fol-
lows:
FiberAlert:
Remote site only
LinkLoss:
Central and remote site
This will ensure that most faults can be detected by an administrator
located at the central site, no matter where they occur on the network.
If you are unsure of how best to implement these features in your con-
figuration, please contact IMC Networks Technical Support at
(800) 624-1070 (U.S. and Canada); +32-16-550880 (Europe).
Installation Troubleshooting
• During installation, first test your fiber and twisted pair connections
with all troubleshooting features disabled. Then enable these fea-
tures, if desired, just before final installation. This will reduce the
features’ interference with testing.
• To
test
McBasic TP/FO by itself, you must have an appropriate fiber
patch cable. First, connect McBasic TP/FO to the twisted pair
device with a twisted pair cable. Next, loop a single strand of fiber
from the transmit port to the receive port of your media converter.
Finally, verify that you have both twisted pair and fiber link on your
media converter.
• Make sure that you are using the appropriate twisted pair cable or
have the crossover/pass-through button on the media converter set
correctly.
4
F
I B E R A L E R T
/ L
I N K
L
O S S
C
O M P A R E D
Feature
FiberAlert
LinkLoss
Fault Location
Fiber
Fiber
Disabled LEDs
Fiber
Twisted Pair
