The dawn of the digital age began in World War Two with the invention of secret computers to break German codes. More generally, the war inspired huge advances in electronics on both sides of the Atlantic. By the end of the 1940s, it was clear that the future belonged to computers.
It was the telecommunications industry that had provided the bulk of the components and expertise from which the first computers were assembled. In the end, the favour was returned because it was in telecommunications that the new computers were able to make their biggest early impacts.
Solid-state electronics, based on transistors and silicon, were beginning to replace bulky and fragile glowing valves of the 1940s.
The future of telephone switching no longer belonged to mechanics and electromagnetism - but to electronics and digital pulses. Realising this was one thing - making the transition was quite another.
The late 1960s saw the start of the move from the old mechanical exchanges with their noisy banks of selectors, switch arms and electromagnets, to the electronic exchanges of the future - silent, compact and far more capable. In the process something else was created - switching that had logic that could be programmed and memory. Machine intelligence had arrived on the telephone network.
This would turn out to be one of the biggest and most ambitious investment projects in its history - and would make Britain's telecomms network into one of the most advanced in the world.
As networks were getting smarter, so too were the phones and other devices being attached to those networks.
Before long, telephone users were able to do a range of things they'd never been able to before.
There was a technical problem. Television pictures carry a lot of signal information - more than ordinary phone lines can accommodate.
There was a human issue, too. The truth is that people don't always want to be seen on the phone. But it took the pioneers of videophones a little while to learn that lesson.
One computer is a computer. Two or more connected and able to exchange data, make a network. Allowing computers to talk to each was one of the great technological challenges of the late 20th century.
At various stages, these solutions were hailed as 'the future'.
Since the late 1990s e-mail has started to reach every area of our lives, transforming the way we organise our work and social time.
Up to 50 million people are using e-mail worldwide. Not all that many yet, but the number is still doubling every two years. The growth of e-mail traffic has been even more rapid. There were around 2,000 million e-mails sent during 1998. By 2001 the annual traffic had grown six fold to around 12 billion - and it's still increasing at about 50 per cent a year.
By the time the world started to get online in the mid 1990s, the Net had been almost 40 years in the making.
Take a look at our free and exciting secondary education learning resource for a more detailed history of the Internet.
Convergence doesn't just mean telephones meeting computers on the Internet - it also means digital and Internet-based technologies impacting on every aspect of communication. Everything is digital now, including our old friends television and radio. The old waveforms are being replaced by digital streams of ones and zeros that do all the old things - but faster, cheaper and better.
A film, a television or radio programme, a song, a message - they're all different - yet in essence all the same - they can all be reduced to a stream of ones and zeros and pumped down the line (or over the airwaves).
This revolution is still in its infancy so it's difficult to say where it might be taking us. But it is possible to trace some of the milestones passed so far.
