Any internet users, whether they are employees working from home or network managers of large enterprises, want to transmit voice, digital and video information through phone lines at fast and cheap basis. The opportunities provided by ISDN permit using one individual line to deploy small office’s telephony or implement additional phone to field important calls or one-time connect the Internet.
Integral Service Digital Network provides all-digital tunnels between stations and supports wide range of voice related and information services, such as:
- digital telephony;
- video telephony;
- remote access to local area network (LAN);
- dialup and non-switched internet access;
- high speed and reliability of information transfer at 128 Kb/sec or simultaneous usage of telephone and Internet at 64 Kb/sec;
- data operation;
- video conferences;
- digital facsimile communications;
- value added ISDN services.
Unlike usual standard analogue telephone network, ISDN is better protected against electric interferences and inaccessible to listening devices.
ISD Network provides integrated assistance and transmits voice, data packages and video messages through one net combined with phone system, leased lines for data exchange and closed circuit TV system.
ISDN access types
- BRI (Basic Rate Interface) refers to use standard line reaching basic rate access. This particular method is designed for small enterprises and home users using one phoneline for two simultaneous conversations or contemporaneously conduct a talk and browse the Internet. Basic interface of network access consists of three separated channels – two bearer channels (or B-channels designed for voice transmission) and one data channel (D-channel), for this reason it’s noted as 2B+D. Each B-channel provides 64 Kb/sec speed, and D-channel transfers info at 16 Kb/sec.
- PRI (Primary Rate Interface) contains 30 B-channels and one D-channel operated at the same 64 Kb/sec speed. As in the previous method, B-channels deals with data transmission, and D-channel service information. PRI is generally intended for telephone line tapping of medium and large organizations, Business Service Centers etc. For the purpose connecting the net, administrators install mini-ATC (Private Automated Branch Exchange) which is connected with one or more ISDN PRI channels, and finally abonents enter the net via the ATC.