Nortel Networks 553-3001-211 manual NT5D11 and NT5D14 Lineside T1 Interface cards Page 185

NT5D11 and NT5D14 Lineside T1 Interface cards Page 185 of 894

Note: Note: The STATUS LED indicates the enabled/disabled status of both card slots of the lineside T1 card simultaneously. To properly enable the card, both the motherboard and the daughterboard slots must be enabled. The STATUS LED will turn off as soon as either one of the lineside T1 card slots have been enabled. No LED operation will be observed when the second card slot is enabled. To properly disable the card, both card slots must be disabled. The LED will not turn on until both card slots have been disabled.

The RED ALARM LED indicates that the lineside T1 card has detected an alarm condition from the T1 link. Alarm conditions can include such conditions as not receiving a signal or the signal has exceeded bit error thresholds or frame slip thresholds. See “Man-Machine T1 maintenance interface software” on page 213 for information on T1 link maintenance.

If one of these alarm conditions is detected, this red LED will light. Yellow alarm indication is sent to the far-end as long as the near-end remains in a red alarm condition. Depending on how the Man-Machine Interface (MMI) is configured, this LED remains lit until the following actions occur:

•If the “Self-Clearing” function has been enabled in the MMI, the LED clears the alarm when the alarm condition is no longer detected. This is the factory default.

•If the “Self-Clearing” function has not been enabled or it has been subsequently disabled in the MMI, the LED will stay lit until the command “Clear Alarm” has been typed in the MMI, even though the carrier automatically returned to service when the alarm condition was no longer detected.

The YELLOW ALARM LED indicates that the lineside T1 card has detected a yellow alarm signal from the terminal equipment side of the T1 link. See the “Man-Machine T1 maintenance interface software” on page 213 for information on T1 link maintenance. If the terminal equipment detects a red alarm condition, such as not receiving a signal or the signal has exceeded bit error thresholds or frame slip thresholds, it can send a yellow alarm signal to the lineside T1 card, depending on whether or not the terminal equipment supports this feature. If a yellow alarm signal is detected, this LED will light.

The MAINT LED indicates if the lineside T1 card is fully operational because of certain maintenance commands being issued through the MMI. See

Circuit Card Description and Installation