User Manual

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User Manual
The previous table reports a brief description of the TFLN alarms, together
with a reference to the corresponding alerted LEDs.
As the table shows, LEDs on the TFLN front panel signal all high priority
alarms while minor alarms, which detect critical situations which should be
checked and tested in order to avoid future possible system faults, are only
revealed by LMT or supervision system.
Each TFLN is provided with an AGC system which compensates optical losses
<3 dB. TFLN LED alarms switch on when the estimated optical losses are
>4dB, the AGC not being able to compensate these losses any more.
One of LEDs 1, 2, 3 or 4 might turn on not only to indicate a high optical loss
detected by TFLN, but also to reveal a remote unit failure. Understanding the
reason why one of LEDs 1, 2, 3 or 4 is on (a remote unit failure, an optical
cable fault or an external equipment malfunction) can be done following the
troubleshooting procedure reported hereinafter.
Quick troubleshooting procedure
(The following procedure is summarized by the flow-chart in fig. 5.15a)
1. In case the TFLN general alarm (LED ┌┘) is on replace the faulty TFLN
master optical TRX with a new one and contact the manufacturer for
assistance.
2. In case one of the LEDs 1, 2, 3 or 4 is on, the corresponding TFLN
adapter might be dirty. Try cleaning it using pure ethyl alcohol. If the
LED is still on go to the corresponding remote unit side and check the
red LED upon TFAx warm side:
a. If it is off, the optical cables or the optical connections are
supposed to have some problem on UL path. Refer to fibre optic
UL troubleshooting for more information (fig. 21).
b. If it is on, refer to remote unit troubleshooting presented in the
previous remote unit section
Fibre optic UL troubleshooting
(The following procedure is summarized by the flow-chart in fig. 5.15b)
1. Check if there is any point where the fibre experiences a small radius of
curvature. In this case, rearrange the optical path in order to avoid
sharp bends (if necessary, replace the optical cable with a longer one). If
this makes the TFLN red LED switch off, troubleshooting has been
successful. Otherwise, follow next steps.
2. Check if the SC-APC connectors are properly installed at both fibre ends
(i.e. TFLN and TFAx ports). If not fix better SC-SPC connectors to
relevant adapters. If this makes the TFLN red LED switch off,
troubleshooting has been successful. Otherwise, follow next steps.
3. Disconnect the optical fibre and clean it at both fibre ends (i.e. TFLN side
and TFAx side) then reconnect the fibre to relevant ports. In case this
makes the TFLN red LED switch off, troubleshooting has been successful.
Otherwise, follow next steps.
4. Disconnect the optical SC-APC connector from TFLN UL port, and
measure the output power P
OUT
(UL) at corresponding fibre end. Then, go
TFLN