Nortel Networks 553-3001-211 manual NTAK79 LEDs Part 2, Red

		NTAK79 2.0 Mb PRI card Page 735 of 894
Table 234
NTAK79 LEDs (Part 2 of 3)
LED	State	Definition
RED	On (Red)	A red alarm state has been detected. This represents
		a local alarm state of:
		Loss of Carrier (LOS)
		Loss of Frame (LFAS), or
		Loss of CRC Multiframe (LMAS).
	Off	No red (local) alarm.
YEL	On (Yellow)	A yellow alarm state has been detected. This
		represents a remote alarm indication from the far
		end. The alarm can be either Alarm Indication (AIS)
		or Remote Alarm (RAI).
	Off	No yellow (remote) alarm.
LBK	On (Green)	2 MB PRI is in loop-back mode.
	Off	2 MB PRI is not in loop-back mode.
CC	On (Red)	The clock controller is switched on and has been
		disabled by the software.
	On (Green)	The clock controller is switched on and is either
		locked to a reference or in free run mode.
	Flashing (Green)	The clock controller is switched on and attempting to
		lock on to a reference (tracking mode). If the LED
		flashes continuously over an extended period of
		time, check the CC STAT in LD 60. If the CC is
		tracking this can be an acceptable state. Check for
		slips and related clock controller error conditions. If
		none exist, then this state is acceptable, and the
		flashing is identifying jitter on the reference.

Circuit Card Description and Installation