When AIS in TS16 is detected, then bit 6 of outgoing TS16 frame 0 should be set. When the
fault disappears, it should be cleared. Setting and clearing bit 6 of TRS 16 frame 0 must follow
changes in status of the fault by less than 100 msec.
Other requirements when AIS 64 Kbit is detected include setting an LED, printing a TTY
message, and updating present status and history files. When a fault is detected, further
changes in other error types should continue to be reported.
Loss of Multiframe Alignment Signal (LMAS). This condition is sometimes called a multiframe
Yellow alarm. An LMAS occurs when two consecutive multiframes contain errors in their
Multiframe Alignment Signal, or when all TS16 bits are zero for at least one multiframe.
B6 alarm is sent to the far end after the persistence time expires. If the option is enabled, a B3
alarm is also sent.
Loss of CRC-4 Multiframe Alignment Signal. This condition is declared when the CRC-4
multiframe search fails to recognize two valid multiframe alignment words within 8 msec. This
category is only relevant however, when the CRC-4 option is selected.
B6 alarm is sent to the far end after persistence time expires. If the option is enabled, a B3
alarm is also sent.
Remote Alarm Indication (RAI). Bit 3 of TS0 in non-FAS frames is set to "one". This alarm is
sometimes called a Yellow alarm. The far end is receiving AIS.
Remote Yellow alarm (B6). Bit 6 of TS16 in Frame 0 is "1". This alarm occurs when the far end
has detected a loss of MFA.
Alarm threshold recommendations for digital trunks
If a digital trunk is present in an IP expansion cabinet/Media Gateway, link outages due to data
network degradation between a main cabinet/Call Server and an expansion cabinet/Media
Gateway cause alarms on the far end of the digital trunk. If link outages are frequent, increase
alarm thresholds on the far end to prevent the trunk from being placed in a state that requires
manual intervention to recover.
NTAK10 faceplate LEDS
The NTAK10 2.0 Mb DTI circuit card has a total of six LEDs on its face. Five of the LEDs are
directly associated with the operation of the NTAK10 2.0 Mb DTI circuit card. The remaining
LED is associated with the on-board clock controller. Table 64: NTAK10 faceplate LEDs on
page 136
shows the LEDs found on the NTAK10 2.0 Mb DTI circuit card and the meaning of
each.
Monitor system DTI operation
ISDN Primary Rate Interface Maintenance November 2011 135
To Next Page
Loading...
Need help?
General
