Specifications

MultiModem ISI Hybrid Series, ISIHI-2S/2U 9
Chapter 1—Introduction
Terminal Adapter Description/Features
ISIHI-2S/2U terminal adapters have S/T ports to connect to the ISDN network and analog
ports to connect to a telephone, modem, or fax machine. They ship with a software
configuration utility for Windows® 95, Windows NT, and ConfigMenu (a built-in
configuration utility for DOS and Windows 3.x operating systems). The TAs also accept
AT commands, enabling them to use the same communications software as analog
modems.
ISIHI-2S/2U terminal adapters are compatible with EuroISDN switch protocol. They
communicate using ISDN BRI (2B+D) service, which provides up to 128 Kbps data and
voice communications. They automatically detect whether an incoming call is voice or
data and handle it appropriately.
The ISIHI-2S/2U terminal adapters communicate over public ISDN telephone lines.
Features include the following:
 Compatibility with NET3, AT&T 5ESS, NT DMS-100, US National ISDN-1switch
protocols
 Automatically detect if incoming call is voice or data
 ISDN BRI (2B+D)
 AT command and S-Register controls and Result Code responses
 Use the same communications software as existing analog modems
 V.120, or PPP compatible
 Supports PPP (Point-to-Point Protocol) high speed ISDN connections
 Windows NT and Windows 95 software utility and a firmware utility for easy ISDN line
configuration
 Flash PROM for easy firmware upgrades
 Automatic detection of the data protocol for answering incoming data calls
 Embedded protocol analyzer for troubleshooting the connection to the ISDN network
The ISDN TAs provide data communication using Basic Rate Interface (BRI). They
provide two 64 Kbps bearer channels for voice or data and one 16 Kbps D channel for
signaling information (2B+D) and are compatible with V.120 and PPP.
The TAs provides dial-up asynchronous communication capability with other personal
computers, terminals, online computer services, or other types of computer systems.
What is a S/T-Interface? An ISDN Basic Rate (BRI) U-Loop consists of 2 conductors
from the CO (telephone company central office) to the customer premises. Equipment on
both sides of the U-loop is carefully designed to deal with the long length of the U-loop
and the noisy environment it operates in. At the customer premises, the U-loop is
terminated by an NT1 (network termination 1) device. An NT1 (network terminator 1) is
a device that provides an interface between the two-wire twisted-pairs used by telephone
companies in their ISDN BRI network and an end-users four wire terminal equipment.
The NT1 drives an S/T-bus that usually is 4 wires but in some cases may be 6 or 8 wires.