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NEAX2400 ICS ISDN PRI Installation Notes
1.
GENERAL DESCRIPTION
This ETI describes the installation procedures and office data assignment for connecting ISDN
lines to NEAX2400 ICS. The ISDN PRI (Primary Rate Interface 23B + D) allows a station user to
gain access to a variety of services, associated with the ISDN, based on the office data assigned.
This ETI, which is not intended as a general ISDN training document, assumes the craft person is
fully trained in the programming and installation of the NEAX2400 and has the necessary ISDN
knowledge.
2.
ISDN OVERVIEW
2.1
Layer 1 Physical Interface
ISDN PRI is a T1 interface which should be configured to ESF B8ZS rather than to D4
AMI. Configuration to ESF B8ZS will avoid falls framing and yellow alarm emulation
problems that can occur when digital data is transported with a D4 format. If ESF with B8ZS
is unavailable, the D channel speed should be set for 56Kbpps instead of 64Kbpps. This
speed setting also applies to data transmitted over the B channels. See
Switch Settings.
ISDN PRI uses out-of-band message oriented signaling, carried in a separate digital (or "D")
channel. The D channel in any PRI interface must be in time slots 24 of the DS1. The
remainder of the 23 bearer (or "B") channels carry voice or data.
When multiple DS1s for ISDN PRI are provided to a given customer location, two methods
of using D channels are used. The first method uses a D channel for each interface. The
second method uses one D channel for several interfaces; this is called Non-Facility
Associated Signaling (NFAS). A D channel backup may be provided in the case of NFAS.
This channel is in stand-by mode and will take over in case of primary D channel failure.
Please note that there are two assignments in ATRK for any ISDN D channel. One
assignment represents the Physical channel on the 24PRT; the second assignment represents
the D channel handler (DCH) part of the 24PRT.
2.2
ISDN PRI Protocol
ISDN protocol depends on the switch type used by the central office. You should have this
information prior to installation since switch settings and data assignment are different for
each protocol.
The NEAX2400 supports AT&T 4ESS and 5ESS protocol, as well as NT DMS100/
DMS250. Currently, the NEAX2400 does not support the National ISDN protocol for PRI.
Arrangements should be made with the central office to configure the protocol for custom
and not for National ISDN PRI. The National ISDN PRI is mostly used in AT&T 5ESS and
NT DMS100/250. AT&T 4ESS only supports AT&T protocol at this time.
ISDN PRI protocol can be broken into two types of protocol. The first type, User to Network
Protocol, allows connection of a PBX to a network. The second type, Symmetrical Protocol,
allows PBX to PBX connection via private lines.
ETI-152A
Table 2
for 24PRT
Page 2
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