Nortel Networks Circuit Card - Manual (Page 257)

NT5D33 and NT5D34 Lineside E1 Interface cards Page 257 of 906
Circuit Card Description and Installation
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.