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Telegraph was the first device of the telecommunications age.

It may seem primitive compared to today's technology, but the telegraph was the wonder of its age. It used the new sciences of electricity and electromagnetismto send information over long distances almost instantly.

Even today telegraph's 'ons' and 'offs' live on the binary codes used by digital technology.

How the telegraph works
The telegraph key is simply a switch in an electric circuit that turns on an electric current. As the sender taps out a word the switch completes a circuit which allows an electric current to flow around it...
Wires and circuits
Electricity needs an unbroken, continuous path for the current to flow along. This path - the electric circuit - needs a voltage from a battery or an electrical generator to push the current around it, and it's the current that powers the machine at the other end....
Loss and noise
One of the facts of life is that nothing's perfect. There is no such thing as a perfect cable, where everything you put in comes out at the other end....
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...