Mitel 3300 Technician's Handbook page 363

BRI NSU LED States
Fifteen circuit LEDs and one status LED are mounted on the faceplate.
The status LED shows the status of the CEPT link, and each of the circuit
LEDs shows the status of one BRI circuit. The BRI circuit LEDs are also
used during card initialization to indicate the progress of the self-test and
to indicate that the download is in progress.
Table 88: BRI NSU CEPT LED States
LED Status
ON
Flashing
OFF
Meaning
Call in progress on DPNSS link.
1 second cycle: Layer 1 established.
4 seconds cycle: Layer 2 established.
CEPT link not established.
Status LEDs
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