"Tech Talk Definition -ISDN"

T1 - For Internet, Voice and Local Phone Service

How does an Integrated Services Digital Network (ISDN) work, and what is a good definition?

ISDN is a digital phone connection system that has been available to many telecommunication services customers since the early 1990s. By definition, ISDN uses ones and zeros to transfer digitized data through an integrated services network. This is the same type of ones and zeros data that your computer uses. To better define ISDN, it first helps to take a look at analog definition.

The analog method, also known as Plain Old Telephone System (POTS), has to convert audio signal to these ones and zeros, transmit it to the next access location, and then reassemble it from the digitized data back into audio format to be received on the other end.

This results in a transfer rate of 56 Kilobytes per second (Kbps). ISDN will operate at 128 Kbps using the ones and zeros for connectivity from end-to-end in order to transmit data instantly across the world. There is an obvious difference of varying speeds that allows ISDN to provide telecommunication services capabilities not really available to analog customers, such as video conferencing or multimedia presentations.

To further breakdown the definition, ISDN has two basic rates of connection services. The Basic Rate Interface (BRI) will meet the telecommunication services needs of most individual customers. BRI transmits data at a digital access rate of up to 144 Kbps.

It accomplishes this by connecting together two standard 64 Kbps channels with a 16 Kbps digital channel. The second ISDN service is the Primary Rate Interface (PRI), which is more ideal for the telecommunication services customers that have greater demand requirements for the capacity of digital transfers. By combining channels, the PRI achieves a digital transfer rate of up to 1,536 Kbps.

In answer to the original question, speed is the simplest definition. ISDN provides greater data transfer capabilities than analog. And while broadband Internet services such as Cable Modem and DSL are displacing ISDN services, these services are not yet available everywhere, making ISDN a viable option for maximizing digital data transfer needs.