3Com CoreBuilder 7000 Installation & Start?Up Manual page 53

Figure 11 DS-3 Status LEDs
Table 13 DS-3 Status LEDs
LED
LOS
Loss of Signal
FERF
Far End Rx Failure
Signal
AIS
Alarm Indication
Signal
LOF
Loss of Frame
4-Port Interface Module LEDs
Color Description
Green On: There is a signal on Rx (normal state).
Off: No signal on Rx (problem with Rx).
Yellow On: FERF in incoming frames (the peer reports
about its Rx problem).
Off: No FERF in incoming frame.
Blue On: AIS signal is present for at least 5 sec. (the
peer reports about its problem).
Off: No AIS signal present for at least 5 sec.
(normal state).
Red On: LOF is present for at least 5 sec. (problems
with Rx).
Off: No LOF for at least 15 sec.
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