A SERVICE OF

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Monitoring the Unit
6-7
7924-A2-GB20-30
October 1997
V.35-Compatible Unit
The green PWR LED lights whenever power is applied to the board. Loop LEDs
blink until the loop has been synchronized and then remain off.
TERMINAL
T1 HDSL
DTR
DSR
Loop Bk
PWR
FAIL
Loop A
Loop B
7900
CTS
RTS
RXD
TXD
97-15313
LED Meaning
Loop Bk ON: A loopback has been initiated for testing the equipment connected to
this unit. Refer to Chapter 7,
Testing
, for more information.
PWR ON: Power is applied to the unit.
FAIL ON: The processor has halted and repairs are required.
Loop A ON: HDSL Loop A has failed.
Blinking: HDSL Loop A is synchronizing with the far-end unit (such as
when the units are coming up after a reset). If the LED blinks for more
than 60 seconds, loss of signal has occurred.
Off: Loop A is enabled and synchronized.
Loop B ON: HDSL Loop B has been disabled (only Loop A is in use) or has
failed.
Blinking: HDSL Loop B is synchronizing with the far-end unit (such as
when the units are coming up after a reset). If the LED blinks for more
than 60 seconds, loss of signal has occurred.
Off: Loop B is enabled and synchronized.