Functional description 271
— maintenance diagnostics
•interface with the line card circuit
— converts on/off-hook, and ringer control messages from the DS-30X
loop into A/B bit manipulations for each time slot in the E1 data
stream, using channel associated signaling.
•the front panel LED when the card is enabled or disabled by instructions
from the NT8D01 controller card.
Card LAN interface
Maintenance data is exchanged with the Common Equipment CPU over a
dedicated asynchronous serial network called the Card LAN link. The Card
LAN link is described in "Card LAN link" (page 25).
Sanity Timer
The LEI also contains a sanity timer that resets the microcontroller in the
event of a loss of program control. If the timer is not properly serviced
by the microcontroller, it times out and causes the microcontroller to be
hardware-reset. If the microcontroller loses control and fails to service the
sanity timer at least once per second, the sanity timer automatically resets
the microcontroller restoring program control.
Man-Machine Interface
The LEI provides an optional Man-Machine Interface (MMI) that is primarily
used for E1 link performance monitoring and problemdiagnosis. The MMI
provides alarm notification, E1 link performance reporting, and fault isolation
testing. The interface is accessed through connections from the I/O panel to
a terminal or modem. Multiple cards (up to 64) can be ser vedthrough one
MMI terminal or modem by linking the LEIs through a daisy chain.
The MMI is an optional feature, since all E1 configuration settings are
performed through dip switch settings or preconfigured factory default
settings. Available MMI commands, and their functionality, are discussed
in-depth in "Man-Machine E1 maintenance interface software" (page 292).
ELEI additional functionality
As mentioned earlier, ELEI cards are enhanced to allow CAS+ compliance,
as shown in Figure 58 "CAS+ compliance" (page 272). This enhancement
provides severaladditional benefits for systems with ELEI cardsinstalled.
Note: MDECTS and ELEI (operating in enhanced mode) cannot be
configured on the same system.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright© 2003-2008, Nor tel Networks
.