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Into the networked age

Datel publicity leaflet (1974)

Datel : telegraph in the computer age

By the 1970s, the telegraph network was more than 130 years old - but it still had a few tricks up its sleeve.

One of these was data networking. As the need increased to send data between computers, it was discovered that the telex network could be used.

Rather than send text and numbers between telex machines, the network could be used to send data between computers. All that was needed was a tape punch - downloading the data from the computer onto rolls of paper tape. These were then fed into a tape reader, to be sent over the network.

The other benefit of this system was that the paper tapes also formed a data back up and a physical record of transactions - albeit a bulky one.

Packet Switching System publicity literature, 1989

Data networks : pioneer computer networking system

In today's digital world, voice traffic, images and data all use the same broadband integrated services digital network (ISDN). Things were different 25 years ago; there was one network for voice, others for television, telex and data transmission - and they were all analogue.

Companies, banks and universities needed to exchange data between sites in those pre-Internet days, but the techniques and facilities they used were very different - they had to use modems to adapt data to the analogue circuits they used.

Dial-up telephone lines handled transmission up to 4.8kbit/s, with higher data rates carried over wideband leased lines (or private circuits) operating at 48kbit/s (about the maximum rates of dial-up phone lines today).

A major breakthrough was the opening in 1977 of the first public Packet Switching System (PSS) circuit, with links operating at 48kbit/s. This was the analogue forerunner of ISDN, which opened for service in London during 1985. 

Checking train times using Teletext

Pre-Internet online services : remembering way back when

As the 1960s turned into the 1970s new mass information systems were devised using people's television screens for display.

Two alternative distribution methods were used, either piggybacked on a television signal as teletext, a semi-interactive system which is still in use, or online by telephone line as viewdata, fully interactive, but not a public service any more. Prestel was the British Post Office's viewdata service.

The display limitations of a television screen meant that only 40 characters could be displayed per line in a text-only system, although developers worked out a way to create some ingenious but blocky pictures out of text graphic characters, the system remained text-based only.

The modem speed was slow by modern standards but, being text only, the pages downloaded rapidly nonetheless. The overall experience was similar to the World Wide Web, only information was directly accessed from a single computer, rather than from mulitple servers, and pages were accessed using numeric addresses typed on the TV's remote control.

The service offered basic commercial services such as banking, e-mail and travel booking - in fact the travel industry still uses a similar service today.

Prestel advertisement

Viewdata and Prestel (1978) : the Internet's auntie

Before the Internet, Britain had its own commercial, online, networked service that would transmit data, offer online services and exchange electronic mails - all the things you can do on the Internet.

This service was based on a system called Viewdata, or videotex, equipped with a built-in modem and the TV's remote control. The same display technology powers Teletext on your television.

Later the Post Office renamed it Prestel, with 'viewdata' becoming the generic name for the method of transmission. Experimental operations began in 1978. For sending and receiving messages customers used adapted television sets equipped with a built-in modem.

The system used the same principle as the Internet - computer data carried via the phone line. It also anticipated today's digital television services by using the television as the display unit.

But Britain was not ready for online services - and by the time it was, the Internet and PCs had made Prestel all but obsolete. Even so Prestel still serves a small market, mainly in travel agencies.

Datel Modem No. 1A, 1964

Modems : there must be something better

Modem stands for MOdulator DEModulator. It sounds quite complex but users need have no fear.

The modulator section turns the digital bit stream (all those ones and zeroes) into a 'sound stream' that the telephone line can handle as a signal.

The demodulator decodes that sound signal back into the original digital code.

This is quite primitive technology, which is why modems are so slow. The fastest modems used today are 56 kilobits per second (Kbit/s) - but in practice, the limitations of the analogue telephone line means transmission speeds don't quite reach that level.

Swiping a credit card

ATMs and EDI : networking everything

High-speed digital data networks may work out of sight and out of mind - but without them modern life just wouldn't function.

Take cash dispensers for instance - or Automatic Teller Machines (ATMs) to give them their correct name. ATMs are totally dependent on data communications. Most of these machines connect direct to bank computers over dedicated circuits for speed and security.

Point-of-sale (PoS) terminals in shops - the machines that have replaced cash registers - also depend on dedicated networks.

More recently,  a system called 'chip and pin' has been introduced as a new secure way to pay with credit and debit cards in the UK. Instead of using your signature to verify payments, you'll be asked to enter a four-digit Personal Indentification Number (PIN) known only to you.

The cornerstone of modern commerce is EDI, standing for Electronic Data Interchange. Providing a totally secure communication system, EDI is the artery that carries the data lifeblood of modern business; how much has been earned, what's been sold - and who bought it.

Some businesses are beginning to move to Internet-based systems for this essential data exchange. However, EDI is still seen as more secure.

Transaction telephone - a Connected Earth object, now at Amberley Working Museum.

Transaction telephone (1980s) : card swipes reduce waiting times

Using a credit card in the early 1980s was a pretty painful experience by today's standards. The whole transaction was done by hand, and if the price of the goods was too high, the shop, bar or restaurant had to telephone up the credit card company to get an authorisation code, which gave them permission to put the sale through.

At busy times the retailer could be kept waiting for several minutes, all the time leaving the customer wondering if it was really worth the effort to buy the goods or not!

An alternative was process was introduced with these authorisation telephones. Now the retailer dialled the number, swiped the card through the slot on top and waited for an automatic code to be sent down the line. This was still a long way from making an actual payment online, but it was the first step on the road to today's much slicker operation.

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.

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