3300 ICP Hardware User Guide
246 Release 3.3
Peripheral Unit

Troubleshoot Fiber Interface Module

There are two LEDs on each FIM. The top LED indicates the status of the FIM itself; the bottom
LED indicates the status of the other FIM (the FIM connected to the far end of the fiber optic
cable).
Fiber Interface Module LEDs
FIM LED State Meaning
On In frame synchronization
Off Power off or held in reset
Flashing Out of synchronization (see Notes below) OR Tx or RX cables could be reversed.
Notes:
1. The FIM in the 3300 ICP monitors the synchronization of the clock that appears on
the fiber link coming from the FIM in the peripheral or DSU Cabinet.
2. The FIM in the peripheral or DSU cabinet monitors the synchronization of the clock
that appears on the fiber link from the main control cabinet FIM. This synchronization
state is encoded along with other information and sent back to the main control
cabinet.