BRX-VDSL2 User Guide
30
180-0153-001-R02
9 Troubleshooting Guidelines
Please use the following table of common issues and suggested resolution whenever you are
experiencing issues with a BRX-VDSL2 device.
Note:
When using a VDSL2 Tester, you should set the test set to the suggested Profiles as per
Annex C.
Problem Description
Possible cause(s)
A. Problem with VDSL2 training
1. Upon installing the BRX-VDSL2, the
DSLAM and CPE are no longer able
to achieve synchronization
Verify that DSLAM and CPE pairs are not
mistakenly swapped. If the DSLAM/CPE pairs
are reversed, the BRX-VDSL2 LEDs will still turn
on but the VDSL2 loop will not train properly.
Verify that there is POTS voltage on the DSLAM
pair to power the BRX-VDSL2. The status LED of
each pair of the BRX-VDSL2 provides a quick
visual indicator of the presence of POTS voltage
on the pairs.
With the POTS circuit in the ON-HOOK state, the
voltage measured between TIP and RING on the
DSLAM pair at the BRX-VDSL2 should be
greater than |35Vdc|.
If any of these measurements are not met, you
should make the corrections as per your corporate
standard procedure and re-verify.
2. The user CPE loses synchronization
with the DSLAM after the link was
stable for at least several minutes
You should have the following equipment to help you
troubleshoot the problem:
- VDSL2 Test Set
- Standard Telephone Test set and/or voltmeter
Follow the procedure below:
Disconnect the subscriber house from the xDSL
copper pair(s) at the NID, verify the
synchronization with the DSLAM using the
VDSL2 test set is achieved and stable.
If the synchronization works well, the problem is
likely with the in-house wiring or CPE. You
should follow standard company practice for this
type of problem.
if the VDSL2 test set fails to establish steady
synchronization with the DSLAM, record the
following information during synchronization
events before contacting the support desk of
Positron Access Solutions:
- Downstream and Upstream SNR values
- Upstream and Downstream Bit Allocation Tables
(BAT)
