Front Panel Leds; Table 3. Front Panel Led Indicators - ADTRAN HTU-C NB Installation And Maintenance Practice

HTU-C using Narrowband/Wideband for Litespan Installation and Maintenance Practice
The HTU-C NB/WB for Litespan is designed to operate with a
nominal operating voltage of –48 VDC and a minimum operating
voltage of –40 VDC. The HTU-C NB/WB for Litespan is not
damaged by any steady state voltage below –56.7 VDC.
Current limiting protectors are not required.

Front Panel LEDs

LED indicators mounted on the front panel of the unit provide the status of the HDSL circuit.
See Table 3 for a listing of the front panel LEDs and their indications.
Label Status
Off
LOOP
Green
2
Green Flashing
Off
FAIL
Red
Off
HDSL
Yellow
Red
Off
LP1 /LP2
Green
Yellow
Red
Flashing
* Illuminates upon HTU-C power up. Remains on until the HTU-C is successfully initialized. The length of time
to complete this procedure is dependant on activity of the terminal control processor in the common control
assembly of the Litespan system.
6
NOTE
NOTE

Table 3. Front Panel LED Indicators

Description
Unit is not in armed or loopback state.
Loopback is active on this unit.
Unit is in an armed state but not in loopback.
Unit is initialized and working properly.*
Unit is initializing or unable to operate.*
Both Loops are synchronized with no alarms at the DS1 interface
Both Loops are synchronized, but there is a yellow or red alarm at
the DS1 interface
One or both loops are out of synchronization
No synchronization between HTU-C and HTU-R on loop 1/loop 2
Good signal quality on loop 1/loop 2
Marginal signal quality on loop 1/loop 2
Severely impaired signal quality on loop 1/loop 2
Error detected on either end of loop 1/loop 2
61247002L1-5A