Skip to main content

Modems and Faxes

One thing that has extended the use of the telephone system is the way that new machines, like computers and faxes, have been connected to the existing network - the cables and exchanges that form the telephone infrastructure.

To take advantage of this infrastructure, the machines are designed to work with the existing system. This means that the signals have to be in a range that the telephone wire can handle.

As the telephone is designed to carry speech, you can hear strange whistling sounds coming out of modems and fax machines - they are communicating with each other in the range of the human ear.

How does a fax machine scan? : doing it line by line

How does a fax machine scan? : doing it line by line

How does a modem transmit? : converting data into signals

How does a modem transmit? : converting data into signals

Inside the fax machine : which bit does what?

Inside the fax machine : which bit does what?

Business fax user : Mr E Donald

Eddie Donald, born in 1943, grew up in Fife, Scotland. His family had a phone at home to support his father's work as an engineering contractor.

He was always fascinated by how it worked, but soon learned the science behind it afterwhich the telephone was just accepted as an everyday item.

Eddie became a construction engineer working for an American subsidiary company. They depended on contacting the States via telex, but he was incredulous when the fax was introduced.

audio clip


We lived by the telex.. Before the fax we lived by the telex because messages came in overnight. Our licensed engineering parent company was actually from the United States so we did have this enormous time difference, so the telex was our means of communication up until the time of the fax. The actual fax machine itself, both at the time and since, I regard as one of the most revolutionary developments ever to take place I think. To be able to send a hand written letter to someone at the other side of the world or more pertinently in my case, to be able to send a sketch of what you wanted drawn up, I thought it was truly amazing. I didn't quite understand how it operated at first and when I first heard about them I didn't believe that you would be able to send drawings over the telephone line.

fun and games

Can you beat our games? Explode equipment to see what's inside, hear the changing sounds of telecommunications, see how telecommunications designs have changed over time or send an e-postacard.

what's on

The UK's first permanent gallery dedicated to the history of information and communication technologies opens in the new Information Age gallery at London’s Science Museum.

audio history

Take a trip down memory lane with extracts of the interviews which have been recorded as part of the Connected Earth oral history programme.

featured story

100 years of automatic switching!
In 1912 the GPO installed Britain's first automatic telephone exchange in Epsom.

Discover the early days of the telephone...