5
T
W I S T E D
P
A I R
C
R O S S O V E R
/ P
A S S
-T
H R O U G H
S
W I T C H
All
McPIMs
with twisted pair ports have one RJ-45 connector for a sin-
gle shielded or unshielded twisted pair link segment. Each twisted pair
port features a 2-position switch, located at position
S1
(see page 3 for
location on boards), for selecting a crossover workstation connection or
pass-through repeater/hub connection.
The switch is labeled with “
X”
for a crossover connection (factory
default) and an “
ll
” for a pass-through connection (see diagram on page 3
for
McPIM TP/BNC
configuration). Select the appropriate setting by mov-
ing the switch to the proper position before installing the media conver-
sion module. If uncertain whether crossover or pass-through is needed,
set the switch to the position that makes the link LED glow.
The twisted pair cable for
McLIMs
is determined by the device it is
attached to. If attached to a NIC card, the
McLIM
will use a pass-through
cable, while a crossover cable used for attaching to a switch or other
McLIMs
.
T
W I S T E D
P
A I R
C
A B L E
D
I S T A N C E
The twisted pair port on
McPIM TP/FOs
features a 2-position jumper at
position
JP2
for selecting longer twisted pair cable distances (distances
greater than 100 meters). Place the jumper over both pins for distances
up to 100 meters (factory default). Remove the jumper shunt or place it
on only one pin for distances of 100 meters or more. (
Note
: The product
on the other side of the conversion must be able to support longer cable
distances as well.
)
T
W I S T E D
P
A I R
C
A B L E
T
Y P E
The twisted pair port on
McPIM TP/FOs
features a 2-position jumper,
located at position
JP3
, for selecting either a shielded or unshielded twist-
ed pair link segment. Remove the jumper shunt or place it on only one
pin to select an unshielded twisted pair link segment (factory default).
Place the jumper shunt over both pins to select a shielded twisted pair
link segment. (
Note
: This jumper is not found on -40
McPIM
boards.
)
About LinkLoss and FiberAlert
McPIM TP/FO
and
McLIM
come with the following troubleshooting fea-
tures:
➤
FO/FX LinkLoss
(a.k.a. "
Fiber LinkLoss
" or "
LinkLoss
")
➤
TP/TX LinkLoss
(a.k.a. "
Twisted Pair LinkLoss”
or "
Reverse LinkLoss”
)
➤
FiberAlert
6
FiberAlert
and
LinkLoss
are advanced troubleshooting features that can
help you locate "silent failures" on your network. However, it is vital that
you understand exactly how
FiberAlert
and
LinkLoss
work, and how they
will react in your network configuration, before attempting to install the
enclosed module(s).
Installing modules without understanding the effects of
FiberAlert
and
LinkLoss
can cause perfectly functioning units to appear flawed or
even dead
.
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 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 IMC Networks 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.
W
H A T
I
S
F O / F X L
I N K
L
O S S
?
FO/FX LinkLoss
is a troubleshooting feature. When a fault occurs on the
fiber segment of a conversion,
FO/FX LinkLoss
detects the fault and passes
this information to the twisted pair segment. If a media converter is not
receiving a fiber link,
FO/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.
W
H A T
I
S
T P / T X L
I N K
L
O S S
?
TP/TX LinkLoss
is another troubleshooting feature. When a fault occurs
on the twisted pair segment of a conversion,
TP/TX LinkLoss
detects the
fault and passes this information to the fiber segment. If a media converter
is not receiving a twisted pair link,
TP/TX LinkLoss
disables the transmitter
on the media converter's fiber port.
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
FO/FX LinkLoss
TP/TX LinkLoss
Fault Location
Fiber
Fiber
Twisted Pair
Disabled LEDs
Fiber
Twisted Pair
Fiber