Transition Networks
S4110 Install Guide
33573 Rev. B
Page 11 of 20
Operation
Power and Fiber Status LEDs
The status LEDs (labeled
PWR
and
LINK
are shown below. Use the status LEDs to monitor S4110
operation in the network.
Figure 7: Power and Fiber Status LEDs
The Power and Fiber Status LEDs are described below.
LED Label
Meaning
Operation
PWR
Power
Green ON for power applied to board.
PORT 1
LINK
Fiber Status 1
On = Fiber Signal Detected.
Off = Fiber Signal Not Detected.
PORT 2
LINK
Fiber Status 2
On = Fiber Signal Detected.
Off = Fiber Signal Not Detected.
Link Pass Through (LPT) Feature
This function causes loss of link on one side of a media converter to be passed through to the other side,
so that upstream equipment can see fault conditions that would otherwise be hidden by the media
converters.
The LPT feature allows the Device to monitor the Fiber RX (receive) ports for loss of signal. For example,
when the Fiber #1link on the near end device is lost (1), the local Device turns off the fiber transmit on
Fiber #2 (2), thus, “passing through” the link loss. The remote Device disables the Fiber #1 link to the far-
end device (3), which prevents the loss of valuable data unknowingly transmitted over an invalid link.
Note that although the link from local fiber #2-Tx to remote #2-Rx is disabled, the link from remote #2-Tx
to local #2-Rx is still alive(4). The LPT process is illustrated in the figure below.
Local
Media
Converter
Remote
Media
Converter
①
②
④
③
Near-End
Device
Far-End
Device
Original fault on the Port-1
Local converter turns off the
fiber transmit on port-2
remote converter
disables its Port-1
This direction of link still
valid
#1
#2-Tx
#2-Rx
#1
#2-Rx
#2-Tx
Figure 8: Link Pass Through (LPT)
