Nortel Networks Circuit Card 311 - Manual (Page 269)

Functional description 269
Overview
The LEI card is an IPE line card that provides a cost-effective, all-digital
connection between E1-compatible terminal equipment (such as voice mail
systems, voice response units, trading turrets, etc.) and the system. In
this application, the terminal equipment can be assured access to analog
(500/2500-type) telephone line functionality such as hook flash, SPRE
codes and ringback tones. The LEI supports line supervision features such
as loop and ground start protocols. It can also be used in an off-premise
arrangement where analog (500/2500-type) telephones are extended over
twisted-pair or coaxial E1 with the use of channel bank equipment.
The LEI offers significant improvement over the previous alternatives. For
example, if a digital "trunk-side" connection were used, such as with the
DTI/PRI interface card, "lineside" functionality would not be supported.
Previously, the only way to achieve lineside functionality was to use analog
ports and channel bank equipment. With the LEI, a direct connection is
provided to the IPE. No channel bank equipment is required, resulting in a
more robust and reliable connection.
When used for connecting to third-party applications equipment, the LEI
offers a number of benefits. It is a more cost-effective alternative for
connection because it eliminates the need for expensive channel bank
equipment. The LEI card supports powerful E1 monitoring, and diagnostic
capability. Overall costs for customer applications may also be reduced
because the E1-compatible IPE is often more attractively priced than the
analog-port alternatives.
The LEI is compatible with all IPE-based systems and with standard
public or private CEPT-type carrier facilities. It supports CRC-4- or FAS
only framing formats as well as AMI or HDB3 coding. Because it uses
standard PCM in standard E1 timeslots, existing E1 test equipment remains
compatible for diagnostic and fault isolation purposes. A/B Bit signaling
may be customized according to the user’s system, including the Australian
P2 signaling scheme.
Card interfaces
The LEI passes voice and signaling data over DS-30X loops through the
DS-30X Interface circuits and maintenance data over the card LAN link.
E1 interface circuit
The LEI contains one E1 line-interface circuit which provides 30 individually
configurable voice interfaces to one E1 link in 30 different time slots. The
circuit demultiplexes the 2.56 Mbps DS-30X transmit signaling bitstreams
from the DS-30X network loop and converts it into 2.048 mHz E1 transmit
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
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