Eicon Networks ISDN NT1 Spécifications télécharger pdf (Page 2)

Basic Concepts

In this section you will find out:

• The definition of ISDN

• Basic Rate and Primary Rate ISDN

• What an ISDN line provides to the user

• How ISDN provides services to the user

• What the B and D channels are used for

What is ISDN?

Integrated Services Digital Network is a set of digital transmission protocols defined by the

international standards body for telecommunications, the ITU-T

(previously called the

CCITT). These protocols are accepted as standards by virtually every telecommunications

carrier all over the world.

ISDN complements the traditional telephone system so that a single pair of telephone

wires is capable of carrying voice and data simultaneously. It is a fully digital network

where all devices and applications present themselves in a digital form.

The essential difference between ISDN and the conventional telephone system is that it is

digital not analogue. Information travels as bits rather than as waves. In addition, it also

allows multiple streams of these bits to occupy the same connection, providing the user

with greater versatility of services.

What are the applications for ISDN?

The Integrated Services Digital Network uses the twisted-pair copper telephone line that

would traditionally carry only one voice connection. ISDN can carry more than one

connection over this wire at the same time, and at greater speed. Applications include

telecommuting; simultaneous voice, fax, data and e-mail; inexpensive videoconferencing;

remote broadcasting and high quality audio transmission.

ISDN handles all types of information - voice, data, studio-quality sound, static and moving

images. They are all digitised, and transmitted at high speed.

ISDN can handle many devices and many telephone numbers on the same line. Up to

eight separate telephones, fax machines or computers can be linked to a single Basic

Rate ISDN connection and have different phone numbers assigned to them. (We'll explain

Basic Rate in the following pages).

A Basic Rate ISDN line can support up to two calls at the same time. Any combination of

voice, fax or PC connections can take place at the same time, through the same ISDN

line.

From a digital ISDN telephone you can place a call to an analogue telephone on the PSTN

(Public Switched Telephone Network) and vice-versa. Both networks are interconnected

by the network carrier in a way similar to the connection between the mobile phone

network and the analogue phone network. For the user, it is completely transparent

whether he is calling a GSM telephone, a conventional telephone or an ISDN digital

telephone.

1 2 3 4 5 6 7 ... 55 56

Pas de commentaire

Eicon Networks ISDN NT1 Spécifications Page 2