Xpm Bit Error Ratio Test - Nortel DMS-100 Series Maintenance Manual

10-8 Trouble isolation and correction
The user can access the BERP test from the maintenance (MTC) level of the
MAP terminal. Commands at the BERP level prepare tests continuously or
for a fixed duration.
Link testing
The BERP testing can occur on the DS-1 links that connect the host
controller to the RLCM. To perform the BERP test on a DS-1 link, a
loopback must be present on the transmission path.
The DS-1 loopback is at the P-side of the host XPM and all 24 channels on
the DS-link are looped back. When a DS-1 loopback is used, the tested
DS-1 link must be removed from service.

XPM bit error ratio test

The host XPM performs the XPM bit error ratio test (XBERT) for the
RLCM subsystem. The XBERT is a diagnostic test that performs the
following:
The XBERT detects bit errors in the transmission of high speed data in the
cards of the host XPM. The host XPM is an LGC, LTC, or remote cluster
controller (RCC), and cards in the OPAC.
Note: To use XBERT, the XPM must be equipped with an NT6X69AB
message protocol card or an NT6X69AA message protocol card with an
NT6X79 tone card.
Test conditions
For accurate fault detection, the system runs the XBERT tests on an active
InSv XPM unit. The system can run these XBERT tests on an OOS unit. At
least one unit of the LCM must be InSv.
Note: The user must not use the XBERT as a tool to provide accurate bit
error ratio evaluation. The XBERT does not use the CCITT standard test
patterns in the test procedure of the XBERT. The XBERT uses XPM tone
PCM to provide the 64 kbps test bit stream.
Test types
The XBERT runs two tests that involve the LCM in the OPAC. The test
names and the corresponding cards of the test names appear in the following
table.
297-8211-550 Standard 05.01 August 1999
detects and measures pulse code modulation (PCM) bit errors that occur
in XPM and OPAC cards
commissions DS-1 and PCM-30 links and trunks that the system
physically loops back at the remote end without the use of a remote
node.