Nortel NT1R20 Description page 159

NT5D33 and NTRB34 Line-side E1 Interface Cards
The STATUS LED indicates whether or not the LEI has successfully passed
its self test, and therefore, whether or not it is functional. When the card is
installed, this LED remains lit for two to five seconds as the self-test runs. If
the self-test completes successfully, the LED flashes three times and remains
lit until the card is configured and enabled in software, at which time the LED
goes out. If the LED does not follow the pattern described or operates in any
other manner (such as continually flashing or remaining weakly lit), the card
should be replaced.
Note: The STATUS LED indicates the enabled/disabled status of both
card slots of the LEI simultaneously. To properly enable the card, both
the motherboard and the daughterboard slots must be enabled. The
STATUS LED will turn out as soon as either one of the LEI 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 whether or not the LEI has detected an
alarm condition from the E1 link. Alarm conditions include, but are not
limited to, such conditions as not receiving a signal, the signal has exceeded
bit error thresholds or frame slip thresholds. See "Man-Machine E1
maintenance interface software" on page 165 for information on E1 link
maintenance.
If one of these alarm conditions is detected, this 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 will remain lit until one the following actions occur:
— If the "Self-Clearing" function is enabled in the MMI, the LED will clear
the alarm when the alarm condition is no longer detected (this is the
factory default configuration).
— If the "Self-Clearing" function has not been enabled or it has been
subsequently disabled in the MMI, the LED alarm indication 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.
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Line cards Description