82
ION-B User Manual
TFAM
Case R2
detection is directly carried out through LMT or Supervision System.
ION-B modules are designed in order to exchange information each other: each RU
constantly monitors the optical signal received from its TFLN unit, so as to control optical losses.
Table 3.5.2 shows a brief description of the alarms related to a Cabinet R2 Remote Unit, with a
reference to the corresponding alerted LEDs and to the actions to be carried out in the case
of a fault.
As the table shows, not all the alarms are revealed by the LEDs placed on the Remote Unit
control panel: in fact, LEDs reveal only major alarms (i.e., the high priority ones), whereas the
minor alarms (i.e., the low priority ones) are revealed only by the LMT software or through the
TSUN Supervision System. The minor alarms usually detect critical situations which should be
checked so as to avoid future possible system faults.
start
end
Is the red LED
ON upon the TFAH?
Optical cable or optical
connections are supposed
to have problems on DL
path. Refer to fibre optic DL
troubleshooting (fig.3.16c)
Clean the SC - APC
optical adapters
and connectors
troubleshooting
Is the red LED
ON upon the TFAH?
Yes
Yes
No
No
Figure 3.5.7 (a): Flow-chart describing the quick troubleshooting procedure of a TFAx Case R
1
Note:
Each Remote Unit is provided with an AGC system which comes
in after the optical-to-RF conversion. This AGC can correctly
compensate optical losses when these are estimated to be <3.5
dB. In case optical losses are > 3.5dB, the LMT application and the
ION-B supervision unit will display a “Warning” alarm: the whole
system still work, but AGC is near to its borderline levels.
The red LED switches on when the estimated optical losses are
>4.5dB, the AGC not being able to compensate these losses any
more.
Fig. 3.5.6:
AGC thresholds vs LED alerts
0dBm
-3.5 dBm
-4.5dBm
Normal
Warning
Alarm
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