Integrated Services Digital Network (Isdn) - Toshiba Strata DK14 General Description Manual

Integrated Services Digital Network (ISDN)

ISDN is a set of integrated telecommunications services, available over the public
telecommunications networks. ISDN makes it possible to send, receive and modify information
using telephone lines in ways that were not previously possible, such as:
Dynamic use of individual or groups of standard (POTS), DID, Tie, FX, WATS, 800 lines on
an as-needed basis
Much faster call setup and data transfer up to 128 kbps
Multi-purpose line use, including sharing lines for voice, data, fax, and video
DID functionality based on the number dialed; without needing to reserve a block of numbers
ISDN service comes in two forms:
Primary Rate Interface (PRI) supports 23 or 24 simultaneous voice or data connections. PRI
is similar to digital T-1 service and uses two pairs of wires from your phone company.
Basic Rate Interface (BRI) supports up to two simultaneous connections using a single pair
of wires.
National ISDN standards were first established in 1992. These were formed for all equipment
providers and services to create a common set of functions for these new services. The public
network is in the process of implementing nationwide the National ISDN 2 (NI-2) services and
some locations have started National ISDN 3. Strata DK Release 4.0 is based on NI-2.
ISDN Primary Rate Interface (PRI)
PRI is the larger ISDN interface (via the RPTU) and uses the 23B+D transmission format, which
has 23 64-kbps bearer channels and one 64-kbps data (control) channel, with total bandwidth of
1.544 mbps.
PRI is designed as the trunk interface to the ISDN network. PRI connects the Strata DK424
telephone system to an intra- or inter-LATA communication provider. PRI can be used to send/
receive voice and/or data.
More importantly, PRI can save money by enabling the multiple use of the channels on the PRI
link for a variety of services, such as DID, Tie, FX, WATS, 800, etc., on demand.
This capability to support multiple services and dynamically allocate channel use as needed is
known as the call-by-call feature. PRI lines also support Calling Number Identification Services
(CNIS).
A dealer-supplied, UL listed, Channel Service Unit (CSU) is required between the DK PRI
interface and the PRI line provider interface in most locations of the U.S. In Canada, a CSA
certified DSU/CSU must be installed.
ISDN Basic Rate Interface (BRI)
Strata DK40i and DK424 support BRI S/T. The DK424 and DK40i will support BRI U
Note
basic features in Release 4.2. No supplementary features are offered in theses releases.
BRI is the smaller ISDN interface and provides two simultaneous voice or data connections with a
single interface. BRI uses the 2B+D transmission format which is defined as two 64-kbps bearer
channels and one 16 kbps data (control) channel. The D-channel carries call setup control data.
ISDN BRI station applications allow the connection of ISDN instruments, such as a group IV fax,
PC, computer terminal or port, a LAN bridge, video conferencing terminal, Internet access
devices, LAN access routers, or other devices that benefit from an all digital transmission link.
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Features
System Features
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