ISDNen

ISDN, or Integrated Services Digital Network, is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the traditional circuits of the public switched telephone network. It was developed by the International Telecommunication Union (ITU) and is widely used in Europe and other parts of the world.

ISDN was designed to replace the older analog telephone system, which was limited in its ability to handle digital data. ISDN offers several advantages over analog systems, including faster data transmission rates, improved voice quality, and the ability to carry multiple types of data simultaneously.

There are two main types of ISDN connections: Basic Rate Interface (BRI) and Primary Rate Interface (PRI). BRI consists of two 64-kbps B-channels for data and one 16-kbps D-channel for signaling, providing a total bandwidth of 144 kbps. PRI, on the other hand, offers 23 B-channels and one D-channel in North America, providing a total bandwidth of 1.544 Mbps, or 30 B-channels and one D-channel in Europe, providing a total bandwidth of 2.048 Mbps.

ISDN has been largely replaced by broadband internet connections, such as DSL and fiber-optic cables, in many areas. However, it is still used in some applications, such as remote access to corporate networks and telemedicine, where reliable and secure data transmission is crucial.