Nortel Meridian 1 Option 11C Manual page 72

Page 72 of 126 DTI Maintenance
553-3011-315 Standard 13.00
With respect to the reception of AIS in TS16, AIS 64 Kbits must be detected
when multiframe alignment has been lost and the binary content of TS16 is
95 percent 1, counting on 256 or 512 bits.
When AIS in TS16 is detected, then bit 6 of outgoing TS16 frame 0 should
be set. When the fault disappears, it should then 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 the updating of 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 persistence time expires. If the option is
enables, 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
CRC-4 option is selected.
B6 alarm is sent to the far end after persistence time expires. If the option is
enabled, B3 alarm is also sent.
Remote Alarm Indication (RAI) Bit 3 of TS0 in non-FAS frames is set to
"1". 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.
January 2002