Allied Telesis AT-MCF112VF, SM, LH - Manual (Page 16)

6
Note
Leaving the Link Test switch in the Link Test position will not affect
the operation of the media converter during normal network
operations. However, the MissingLink feature of the media converter
is disabled when the switch is in the Link Test position. Consequently,
it is recommended that the Link Test switch be set to the Normal
position during normal network operations.
Reset Button
The Reset button allows you to reset the ports on the unit. You might need to
reset the ports after completing the installation or after adding or swapping a
power supply. You must reset the unit after a power disruption or whenever a
general power failure status is observed.
MissingLink Feature
The MissingLink

feature enables the twisted pair and fiber optic ports of
each channel on the media converter to pass the “Link” status of their
connections to each other. When a channel detects a problem with one of the
ports, such as the loss of connection to a node, the channel shuts down the
connection to the other port of the channel, thus notifying the node that the
connection has been lost.
For example, Figure 5 illustrates the two ports of Channel 1 on an
AT-MCF106xx unit. The twisted pair port in Channel 1 is connected to a port
on an AT-8224XL Ethernet switch and the fiber optic port is connected to an
AT-FS709FC Ethernet switch. If the fiber optic cable to the AT-FS709FC
switch experiences a failure, the MissingLink feature in the channel will
detect the problem and drop the link on the twisted pair port. In this way, the
AT-MCF106xx unit notifies the AT-8224XL Ethernet switch that the
connection to the AT-FS709FC Ethernet switch has been lost. If the failure
had started with the twisted pair cabling, the MissingLink feature would drop
the link to the fiber optic port.
Figure 5 MissingLink Example
Tx
Rx
Tx
Rx
Tx
Rx
7
8
9
T-LNK
F-LNK
Active
7 7
7
Connected to an
AT-8224XL Ethernet Switch Connected to an
AT-FS709FC Ethernet Switch