Nortel Networks 311

176 NT5D11 and NT5D14 Lineside T1 Interface cards

Lineside T1 card slots are enabled. No LED operation is observed when

the second card slot is enabled. To properly disablethe card, both card

slots must be disabled. The LED does not turn on until both card slots

are disabled.

The RED ALARM LED indicates that the Lineside T1 card has detected

an alarm condition from the T1 link. Alar m conditions can include such

conditions as not receiving a signal or the signal has exceeded bit error

thresholds or frame slip thresholds. See "Functional description" (page

391) for information on T1 link maintenance.

If one of these alarm conditions is detected, this red LED light. Yellow alarm

indication is sent to the far-end as longas 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 stayslit 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 "Functional description" (page 391) 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 yellowalar m signal to the Lineside T1

card, depending on whether or not the terminal equipment supports this

feature. If a yellow alarm signal is detected, the LED lights.

The MAINT LED indicates if the Lineside T1 card is fully operational

because of certain maintenance commands being issued through the

MMI. See "Functional description" (page 391) for information on T1 link

maintenance. If the card detects that tests are being run or that alarms

are disabled through the MMI, the LED lights and remains lit until these

conditions are no longer detected, then it turns off.

Functional description

Figure 31 "Lineside T1 card - block diagram" (page 178) shows a block

diagram of the major functions contained on the Lineside T1 card. Each of

these functions is described on the following pages.

Nortel Communication Server 1000

Circuit Card Reference

NN43001-311 01.04 Standard

Release 5.0 23 May 2008