JDS Uniphase HST-3000 User Manual page 103

Chapter 5 Troubleshooting
Resolving problems
Issue
The modem gets sync with the CO, but the rate is lower than
expected.
Resolution
Verify that you are on a VDSL line.
Check the bits/tone and the SNR/tone (Future feature) for
areas of the spectrum with low throughput. This could be
caused by bridged taps, cable crosstalk, or AM radio.
Use the HST-3000 to check physical conditions: DVOM,
balance, opens, and use the TDR to check for bridged taps.
Check the DSLAM configuration - the max rate may be limited
there.
Check for premise alarm system on the same pair.
Avoid excessive loop length or high attenuation.
Make sure that you are connected on pins 4 and 5.
Verify the noise margin.
Issue
In Bonded VDSL Modem Emulate mode, the pairs are not
bonding.
Resolution
Verify that both pairs support bonding.
Try to bond again by restarting the modems (use the DSL
Stop/DSL Start soft key).
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HST-3000 xDSL Testing User's Guide