ADTRAN HDSL HTU-C/DDM+ - Manual (Page 2)

INDICATIONS AND PROBABLE CAUSES
Front Panel or Circuit Parameters Indicate Abnormal Operation
Connect a terminal emulator via the RS-232 (DB-9) craft interface on faceplate. The terminal
must be VT100 or compatible and set for 1.2 to 19.2 kbps, 8 data bits, no parity, 1 stop bit. Tap
the space bar to establish communication with the unit. Select “M” from the ADTRAN Screen
and “1” from the HDSL main menu. Verify the following conditions on the Current System
Status Screen:
■ Is signal quality fluctuating (graphical meter indicators bouncing up and down)?
■ Is LOSS (pulse attenuation) > 30 dB?
■ Are there any errors counting on the ES, SES, or UAS registers?
■ If signal quality is NOT fluctuating, is it equal on both loops?
■ Is the current signal quality indication (uppermost “x” on the meter) more than 1 dB below
the MAX?
■ Is the current LOSS reading more than 1 dB below the MAX?
If any of these conditions exist, a cable problem is probable and cable testing should be done to
verify all HDSL deployment guidelines are met. These conditions may also reflect intermittent
cable faults or excessive noise impairments. If intermittent faults or noise impairments are
suspected, select “2” from the HDSL main menu and review the Performance History Screen.
If all of the above conditions are met, as well as the HDSL Deployment Guidelines (noted
below), the circuit should provide quality service and can be released.
Front Panel Indications Under Normal Operation:
STATUS ● Green
Circuit Parameters Under Normal Operation:
LOSS < 35dB
Signal quality of 6 dB or higher, with no fluctuation and equal on both loops
All HDSL Deployment Guidelines are met
HDSL DEPLOYMENT GUIDELINES
■ Cable pairs must be non-loaded
■ Total bridged tap < 2.5 kft
■ No single bridged tap > 2 kft
■ 196 kHz insertion loss < 35 dB
■ Pulse attentuation (loss on HDSL current system status screen) 30 dB
■ Maximum loop resistance is 800 Ω
■ Impulse noises < 50 dBm as measured using a 50 kHz filter and quite termination
■ Wideband noise ≤ 31 dBm as measured using a 50 kHz filter and quite termination
HDSL TROUBLESHOOTING GUIDE
PRICING AND AVAILABILITY 800.827.0807
TECH SUPPORT 800.726.8663
RETURN FOR REPAIR 256.963.8722
www.adtran.com
61246003L2-22B