Integrated service digital network
Integrated service digital network definition
A type of digital telephone system that allows for the simultaneous transmission of voice, data, and video over the public switched telephone network. It was developed in the 1980s as a way to improve upon the existing analog telephone system and provide more efficient and reliable communication services. ISDN uses a special type of digital signaling to transmit data over the network, which allows for high-speed communication and the ability to transmit multiple types of data over a single line. This makes it a popular choice for businesses and other organizations that need to communicate large amounts of data quickly and reliably.
Main integrated service digital network iterations
- Basic Rate Interface (BRI) ISDN is an entry-level alternative for standard internet access. It provides two 64 Kbps B-channels and one 16 Kbps D-channel for a total data rate of 144 Kbps. BRI ISDN was typically used for residential and small business applications. It was advertised to provide high-speed digital data transmission and access to advanced communication services. However, ISDN worked over old copper telephone lines, therefore the speed rarely reached 128 Kbps as advertised.
- Primary Rate Interface (PRI) ISDN was mostly intended for larger businesses and organizations and promised higher speeds up to 2.048 Mbps. While BRI only used two channels, PRI employs 23 parallel 64 Kbps bearer channels.
- Broadband ISDN (B-ISDN) was never widely used. It’s an advanced form of ISDN, designed to improve the PRI-ISDN’s performance. It was meant to run over fiber optic cables, uploading and downloading data in hundreds of Mbps. It never became popular because of the development of ADSL technology.