Chapter 2 - Installation

Chapter 2 - Installation

Introduction

This chapter describes how to make all the physical and software driver connections necessary for your terminal adapter to operate in an ISDN environment. Please check the package contents list in Chapter 1 before beginning your installation.

ISDN BRI Line

Before running the ISDN adapter, you need to get an ISDN BRI (Basic Rate Interface) line from your local telephone company. Your ISDN service provider will provide information to you about the ISDN central switch type, pertinent subscriber information and SPID (Service Profile ID) number(s).

SPID (Service Profile ID)

The Service Profile ID (SPID) is applicable in the U.S. only. SPIDs are a series of numbers that inform the central office switch which services and features to provide to an ISDN device. The generic SPID format comprises 14 digits. The first 10 digits are the main telephone number on the terminal. The last 4 digits are dependent on the number of terminals on the interface and the services they support.

NT1 Connection

An ISDN Basic Rate (BRI) U-Loop consists of 2 conductors from the CO (telephone company central office) to the customer premises. The equipment on both sides of the U-loop has been 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 is a device which 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 which is usually made up of 4 wires, but in some cases may be 6 or 8 wires.

The name of the S/T bus comes from the letters used in the ISDN specifications to refer to two reference points, S and T. Point T refers to the connection between the NT1 device and customer supplied equipment. Terminals can connect directly to NT1 at point T, or there may be a PBX (private branch exchange, i.e. a customer-owned telephone exchange). When a PBX is present, point S refers to the connection between the PBX and the terminal. Note that in ISDN terminology, “terminal” can mean any sort of end-user ISDN devices, such as data terminals, telephones, FAX machines, etc. The diagram which follows reflects interface points in a typical ISDN network.

If your ISDN product operates with a S/T outlet interface, you need an NT1 device to connect to the ISDN switch. MT128PCI-SD/SV adapters need an NT1 device to connect to the ISDN switch, but the MT128ISA-UV adapter does not require NT1 device. In the UK, and in many European countries, an NT1 device is supplied by your telephone company.

MT128ISA/PCI

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