Isdn Primary Rate Interface (Pri) - Toshiba Strata DK14 General Description Manual

ISDN Primary Rate Interface (PRI)

PRI is the larger capacity ISDN interface, providing 23 simultaneous voice or data connections.
PRI uses the 23B+D transmission format which is defined as 23 64 kbps bearer channels and one
64 kbps data (control) channel, with total bandwidth of 1.536 Mbps.
ISDN PRI is designed as the bulk trunk interface to the ISDN network. PRI connects the DK424
telephone system to an intra- or inter-LATA communication provider. PRI can be used to send and
receive voice and data.
PRI can save money by enabling the multiple use of the channels on the PRI link for a variety of
services on demand, such as DID, Tie, FX, WATS, 800, etc. This capability to support multiple
services and dynamically allocate channel use as needed is known as the call-by-call feature and is
described in more detail below. PRI lines also support the Calling Number ID Services also
described below.
ISDN PRI is supported in the DK424 system by using the Primary Rate Interface Unit (RPTU).
The RPTU is a 24-channel PRI card providing 1 data (control) channel and 23 bearer channels. All
B-channels appear and program as CO lines in the DK424 system and can be individually
configured for local service, FX, WATS, DID, Tie line, etc. service operation. Network connection
using PRI interface requires a customer supplied external Channel Service Unit (CSU).
The DK424 provides the following ISDN PRI features:
Call-by-Call Service Selection permits the grouping of individual PRI B-channels to be shared
among various types of services specified by the customer, instead of having to dedicate each
channel to a particular type of service. For example, when using standard (POTS), DID, Tie,
FX, WATS, and 800, the line circuits (individual or groups) of B-channels of a PRI circuit can
be designated to these various services dynamically on a call-by-call basis.
B-channels can be dynamically allocated among services on a demand basis, depending on
varying requirements for outgoing and incoming calls. This could also be used for voice or
data on demand. This dynamic allocation of service can reduce the number of circuits required
to access various services, especially if different services have peak busy periods at different
times of the day.
Release 4.2 enables a minimum and maximum number of B-channels to be used for each
service on this common set of B-channels in system programming. Each of these values can be
set for three time periods during the day. With these values, calls can be rejected if they exceed
the maximum number subscribed for that service or they can ensure that a minimum number
of channels remain available for incoming calls. Thus, the system can be used to provide an
optimum service to meet the objectives of the business.
Non-facility Associated Signaling increases traffic handling on PRI lines. A single 64 kbps D-
channel on one PRI line can be used to handle the signaling for two PRI lines on the DK424
system, instead of the usual signaling that requires one 64 kbps D-channel for each PRI line.
Strata DK Feature Description 5/99
System Availability
Unavailable for Strata DK14/DK40i and
DK424 using RCTUA processor
Optional on Strata DK424 using RCTUBA/
BB, RCTUC/D or RCTUE/F processors
Features
System Features
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