Broadband filter systems

The first method of providing internet services to customers was the “dial-up” connection. Using a device called a modem to convert the ones and noughts computer signals to audible tones, the connection was fairly slow; running at 56 kilobits per second. The modem was connected to a telephone line in exactly the same way that an extension telephone is connected.

This method had the major drawback of tying up the telephone line while the internet was in use.

The modern broadband method of connecting a home PC to the internet uses a method called “frequency division multiplexing” to superimpose the internet signals onto the telephone line, and using special filters, these two different services can be easily split off from eachother.

A modem is still used to convert the computer signals to signals suitable for use on a telephone line, but because of the technical differences found on broadband connections, the two kinds of signals do not interfere with eachother, and thereby allowing the telephone to be used normally while the computer is connected to the internet.

Broadband lines are often called ADSL (Asymmetric Digital Subscriber Line).