Nortel Networks 553-3001-211 manual 222 of 894 NT5D11 and NT5D14 Lineside T1 Interface cards

Page 222 of 894 NT5D11 and NT5D14 Lineside T1 Interface cards

Clearing” option has been set. Otherwise, the alarm will continue until the command set Clear Alarm (C A) has been entered.

When an alarm is cleared, the following activity caused by the alarm will be cleared:

•the external alarm hardware will be deactivated (the contact normally open will be reopened)

•the LED light will go out

•an entry will be made in the alarm log of the date and time the alarm was cleared

•carrier fail line supervision will cease (for alarm level 2 only)

If self-clearing alarm indications have been disabled, carrier fail line supervision will terminate when the alarm condition has ceased, but the alarm contact and faceplate LED will remain active until the alarm is cleared.

Note: A heavy bit error rate can cause 150 bit errors to occur in less than 100 seconds. This will cause the alarm to be activated sooner.

An alarm will not be automatically cleared until the system no longer detects the respective bit error threshold during the corresponding duration period. For example, if an AL1 threshold of 6 (representing 10–6) and a duration period of 100 seconds is specified, an alarm will be activated if more than 150 bit errors occur in any 100 second period (1.5 seconds X 100 seconds = 150/ 100 seconds). As soon as the alarm is activated, the bit counter is reset to 0. If the next 100 seconds pass, and less than 150 bit errors are detected, then the alarm will clear after the duration period. However, if more than 150 bit errors are detected in the next 100 seconds, the alarm continues for the designated duration period. The alarm will finally clear when the alarm condition is no longer detected for the designated duration period either by self-clearing (if this function is enabled), or when the Clear Alarm (C A) command set is entered.

In addition to bit errors, the Set Alarm function sets parameters for detecting frame slip errors, by establishing a threshold necessary to activate an alarm. If the threshold value is exceeded, a level 2 alarm will be activated. The frame slip threshold can be specified from 1 to 255 frame slips per time period. The duration time period can be specified from 1 to 24 hours.

553-3001-211 Standard 2.00 September 2004