Table 11. Pair Reversal Key Definitions; Table 12. Hdsl Loop Signal Quality; Table 13. Adtran Noise Margin Guidelines - ADTRAN 220 HTU-C Installation And Maintenance Practice

HDSL 220 Transceiver Unit for Central Office Installation and Maintenance Practice
An indication of Pair Reversal (if present) appears at the bottom of the first key column. Defini-
tions for this key are provided in
and DSX-1 signals is located in the center of the screen near the bottom.
Indicator
FRAME
CODE
LBO
NIU
BPV
ES
SES
UAS
Alarms
A measure of signal quality for each HDSL loop appears on the bottom right and left of the
screen. Guidelines for interpreting the measure indicators are given in
Measure
Predicting performance based upon signal quality varies with each loop. Generally, a noise
margin of 0 or higher will support a bit error rate of better than 10
lines that correspond to the operation of the 220 HTU-C faceplate LEDs labeled LP1 and LP2
are illustrated in Table
Margin = 0
0 < Margin < 4
Margin > 4
20
Table 11. Status and configuration information for the DS1

Table 11. Pair Reversal Key Definitions

Definition
T1 framing format selected
T1 line coded selected
Line Build Out selected (for DSX-1),
Customer signal of 0 or –15 dB (for DS1)
Network interface unit enabled
Bipolar violations detected (DSX-1 and DS1)
Errored seconds (DSX-1 and DS1)
Severely errored seconds (DSX-1 and DS1)
Unavailable seconds (DSX-1 and DS1)
Lists current alarm condition status

Table 12. HDSL Loop Signal Quality

Signal Quality
0
1-3 Marginal
≥ 4
13.

Table 13. ADTRAN Noise Margin Guidelines

Margin LP1/LP2 LED
Red
Yellow
Green
Poor ≤ 0 dB (≈10
above 10
Good ≥ 4 dB above 10
Loop Quality
Poor Loop Quality
Marginal Loop Quality
Good Loop Quality
Table 12.
Noise Margin
–7 BER)
–7 BER in dB
BER
–7
-7 . ADTRAN defined guide-
61247001L1-5A