ISDN

ISDN – Integrated Services Digital Network – is a service provided by telecommunications companies such as British Telecom to enable ordinary telephone lines to carry digital signals. This means that a modem is not needed to convert signals into analogue form. Instead, a device called an ISDN terminal adapter is required. It uses a technique whereby several digital signals can be sent along the same wire. This means that the user can use the telephone, and send or receive data at the same time.

Advantages of ISDN compared with modems:

• The use of ISDN means that data can be transmitted much faster than when a modem is used.
• Data can also be compressed before sending, which increases transmission speed still further.
• Because ISDN equipment is relatively inexpensive, it makes video conferencing accessible to many people. Through a network, typically the Internet, they can talk to and see other people in distant places, and send and receive data at the same time.