Nortel DMS 100 Series Maintenance Manual page 45

If the AMC node initiates a blocking of a line, the system marks the line as
permanent lock out (PLO). An attempt to RTS an MB line while the line is
blocked on the AMC side results in a PLO state for the line.
External bit error rate tests (XBERT)
The following XBERT tests are supported:
• XBERTPSL - Tests a channel looparound on the NTMX82 circuit card.
• XBERTHLP - Tests a given channel looparound on the NTMX82
(excluding channels 0 and 16). Loop the carrier to a digroup looparound
or force the carrier on a digroup looparound. Use the Loop command to
perform this action. The user must perform this action before the
installation of the test.
Carrier maintenance log reports
Log reports are issued for given carrier-related occurrences. The system
generates carrier RTS logs and carrier busy logs when the carrier changes
states. Many logs relate to the maintenance limit (ML) and out-of-service
(OOS) set in table CARRMTC.
Carrier alarms
On CAS interfaces with dedicated channel assignments, failure of a carrier
causes a major alarm. The carrier alarm indicates that the lines on that carrier
lost service. When a fault occurs on an RSC-M carrier, the system can detect
and generate one of the following alarms:
• slips
• frame losses alarms (LLFA, LLMA, LLCMA, RFAI, RMAI)
• additional faults if the far end carrier supports the faults. Additional faults
include AIS, BER, CARD, and CRC4.
The carrier MAP level displays the carrier number according to the class that
reached or exceeded the ML or OOS. The MAP level displays trunk class if
this carrier does not define RSC-M lines. The MAP level displays remote class
if the PCM30 carrier defines RSC-M lines. The PCM30 carrier connects the
RSC-M and the AMC nodes. When carriers exceed the ML or OOS limits, the
system updates the MAP display for the carrier. For OOS limits, the carrier
can be placed OOS. The DISP command allows you to display carriers that
reach the ML or OOS limits.
The DMS switch monitors the signals that transmit between an RSC-M and
lines for frame losses, slips, or other faults. When specifications are not met,
the system increases OMs in the PCMCARR OM group, and ML and OOS
limits. Steady frame loss, excessive frame losses, slips, and bit error rates
(BER) normally cause the system to place a carrier OOS.
DMS-100 Family Remote Switching Center Multi-Access Maintenance Manual XPM11 and up
Maintenance overview 2-29