AT&T Release 2.0 manual CSU Front Panel LEDs, Network Side, System Side, L o r When Lit Indicates

Connecting the Control Unit to the Network Interface

Table 4-18. CSU Front Panel LEDs

L E D

LOCAL POWER

Network Side:

FAR END LOOPED

CRITICAL PWR

PULSES

FRAME LOSS

CRC ERROR

BPV

NEAR END LOOPED ALARM

System Side:

LOOPED

FRAME LOSS

LOW DENS

A C O

	C o l o r				When Lit Indicates
	Yellow
					Local 117 VAC or -48 VDC is ON
		R e d
				Far-end CSU looped if initiated by near-end
				CSU.
	Yellow			Power is on to critical circuits
	Green			Normal incoming signal from network
	Red			Loss of signal, loss of frame synch,
				improper frame sequence, or unframed
				signal
	Red			CRC error detected
	Red			Non-B8ZS violation detected when optioned
				for B8ZS; other bipolar violations detected
	Yellow			Loopback is activated
	R e d			BER threshold exceeded (associated
				contacts for an audible alarm are also
			activated)
	Yellow
			Loopback activated on system side
	Red		Loss of signal, loss of frame synch,
			improper frame sequence, or unframed
			signal
Red			Avg. ones density below threshold or
			consecutive zeroes threshold
Yellow
			Lights when ACO button is pressed when
			ALARM LED is lit

Installing the Channel Service Unit 4-31