Telegraphs & Telex
...connecting the World
Telegraphs and Telex
This section will take a look at the automation of the Telegraph Services from the late 1930s onwards and their evolution into Telex and Datel which were the forerunners of today's dial-up and high speed data links. Much of the early routing apparatus used Strowger switches, housed in shared equipment rooms in some of the major telephone exchanges and trunk centres.

Photo: TASS Final Selectors in Kelvin House, London. [John Lamble C1977]
| EXIT | Telegraphs & Telex | The Public Telegraph Service | The Automatic Telex Service | The Teleprinter Private Services | Datel Services | Prestel | Links | Teleprinters |

The Public Telegraph Service for the transmission and receipt of telegrams (typed messages) generally was established first, followed by the Telephone Service for the transmission of voice messages. Later, private teleprinters were connected via the Telephone Service to give a dial-up form of Private Telegraphs. The telephone network was not suitable for sending telegraphic messages and thus the Telex Service (a separate dial-up teleprinter network) evolved.

Today's legacy copper network still isn't entirely suited to the transmission of fax and Internet traffic, but ingenious signalling techniques and modern equipment overcomes these deficiencies!

The Telegraph Services
By 1969, there were three distinct Telegraph services provided by the Post Office:

  1. The Public Telegraph Service (for the transmission and receipt of telegrams)
  2. The Automatic Telex Service
  3. The Teleprinter Private Services

The Public Telegraph Service
The Public Telegraph Service
The Public Telegraph Service was more commonly known as the Telegram Service because it was for the acceptance, transmission and delivery of Telegrams which used the Telegraph Network.  

Book: Bringers of Good Tidings, with illustrations by Edward Ardizzone.
The Telex Service
The Telex Service
The term, TELEX is the contraction of the two words TELegraph EXchange.

The Telex service in the United Kingdom was a fully automatic teleprinter switching system, which enabled subscribers to call each other at any time - day or night - and to communicate in print.
Calls could also be made to telex subscribers in most other countries.

Image: Post Office Telecommunications - Telex Services brochure 1977.
The Teleprinter Private Services

These were (rented) point to point, or multipoint, private wires designed to carry teleprinter traffic between business customers' premises. Circuits date from (at least) the 1950s and were the forerunners of the later Datel Service.

Typical speeds offered were:

Tariff H 50-baud and Tariff J 75-baud.

In 1970, the equipment consisted of teleprinters 15B and a signalling units TG 2164.

Ref: EI  P.W.s & Telex A3114

Datel Services
Datel Services
The Datel Services were the forerunners of high-speed data modems, KiloStream and MegaStream applications.. DATEL is a contraction of the words, Data and Telecommunications.

Image: Post Office Telecommunications - Datel Services leaflet 1978.
Prestel - The Post Office Viewdata Service
Prestel- The Post Office Viewdata Service
Viewdata was the generic name for the 'new information service from the British Post Office' which was marketed as Prestel.

Image: Viewdata leaflet 1977.

International Telegraphs - A site to remember Post Office and BT people who provided these services from the 1950s to the 1980s.

Telegrams Online offer a personal greetings telegram service. [From July 2003]

Design, images and text compiled by © Light-Straw. With thanks to John Lamble.
Page last updated 4th July 2013. Checked June 2021.

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