Connecting the world

The telegraph allowed us to send messages over long distances faster than people can travel.  Telegraph cables were laid under the sea, and could become home to marine life over time.

A message was sent along the cable in a code of dots and dashes by making and breaking an electrical connection. 


This led to the first global communication network and brought the world closer together.

In 1926, John Logie Baird used this device to demonstrate his invention: television (both sound and pictures). The device had a complicated way of working: lots of different things needed to happen.

First, the disc rotated.  


As the disc rotated, each of the 30 holes scanned a different part of the subject and focused light into Baird’s photosensitive cell.

The light in the photosensitive cell was turned into an electrical signal.

This electrical signal could be sent to a receiver, which showed the image on a glass screen.

Telstar 1 was the first satellite to transmit live black-and-white television pictures from America to the UK and the rest of Europe through space.  Now satellites are used for everything, from television broadcasting to navigation systems in our cars.

Satellite networks transmit images, voice and data to where other communication technologies cannot reach and into our homes and smartphones.

Before everyone had a phone in their pocket, people still needed a way to keep in touch when out of the home. The first standard public telephone kiosks were introduced by the General Post Office in 1921 to make this possible. 

The bright red telephone box was designed to grab attention in towns and cities. To be instantly recognisable, the kiosks had to all be the same shape and colour. 

In 1990, the number of telephone kiosks on the street in the UK peaked at around 100,000 kiosks.

This bright yellow call box from Cameroon in Africa is where people came to fix their mobile phones and buy their call time in the 1990s and 2000s. People who ran the boxes offered mobile phone minutes or telephone calls to customers.

The boxes were often made by their owners, were brightly coloured, and some even sold snacks. 

Nowadays, Cameroon has one of the highest rates of smartphone use in Africa, so these boxes are no longer needed.