Teletex System of Document Transfer Abandoned in The 1990s

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This post is about the teletex system and is not to be confused with teletext, which is a standard for displaying text and basic graphics on suitably equipped televisions. Also, it is not to be confused with telex which is briefly discussed in the last paragraph of this post.

Some Examples of Teletex Terminals

First Image attribution: Federigo Federighi, CC BY-SA 4.0 via Wikimedia Commons. Second image attribution: Hinnerk11, CC BY-SA 4.0 via Wikimedia Commons. Derivative version is greyscaled. Third image: Jvjvjvjv, CC BY-SA 3.0 via Wikimedia Commons.

Scope of This Post

I did not have the opportunity to use a teletex system, but as a telex operator, I was aware of this related communications system being available to UK subscribers in the mid-1980s to early 1990s. Information about teletex on the internet is limited, and the Wikipedia article about teletex is sketchy in information. I had to delve deep into the internet to find out more. There may be errors in my post, and I welcome your thoughts in the comments section at the foot of this post.

Research For This Article

What I found on the internet were quite a few snippets of information about the teletex system but no single document that could explain this system in the detail I wanted for this post. I did find one excellent video by Harald Welte at RetroNetCall entitled Teletex: The brief abandoned step between Telex and Telefax. The author of this video tells us that he did not use the teletex system himself and that he too had to scour the internet to put together his video presentation about teletex. I have made some use of the information I gained from RetroNetCall’s video to put together this post.

Watch The Video

The brief abandoned step between Telex and Telefax.

Background and Intended Use of Teletex

Teletex is an obsolete communications system with parameters set by the ITU-T*. Teletex was a higher specification document transmission system than telex and intended to be a bridge to email and fax.

*ITU-T. International Telecommunication Union Telecommunication Standardisation Sector.

The teletex system existed in Germany (only in West Germany) between 1981 and 1996. The system was also used in Austria, Denmark, Belgium, Finland, France, Netherlands, South Africa, Switzerland, Turkey, the UK and the USA. Source: RetroNetCall’s video referenced above. I am unable to ascertain the start and end dates of teletex in the additional countries mentioned above. I imagine the dates might have been broadly in line with those in Germany.

Teletex could exchange documents with relatively complex layouts, which telex could not do as it was limited in its character set and had no capability for displaying even basic graphics.

Above Image attribution: User: Huestones with derivative work by User: TedColes, CC BY-SA 3.0, via Wikimedia Commons.

In some companies fax machines during the 1980s were still limited to Group 1 and Group 2 specifications. These fax machines could send a page in about 6 minutes and about 3 minutes respectively. The received copy of these fax messages was of poor quality. I remember using one of these Group 1 fax machines in the 1980s and the equipment dimensions were huge. From memory, I would say the machine I used measured about 1 metre wide by 50 cm tall.

What You Could Do With a Teletex Terminal

• Use the terminal as an ordinary electronic typewriter
• Print documents with a connection to a separate printer
• Send and receive documents to and from any teletex terminal in the world
• Send and receive telex messages to a teleprinter terminal as long as that teleprinter was connected to a public switched telex network and the character set used was compatible with the restricted character set limitations that a teleprinter could handle, in accordance with the International Telegraph Alphabet No. 2. Documents intended for a telex recipient needed have a line length restricted to 69 characters, which is the maximum line length most telex terminals could handle*.

*TWX teleprinters such as the Teletype Model 33 in North America were capable of a maximum line length of 74 characters. Source: Teletype Model 33 ASR. While I have not found any documents on the internet to prove otherwise, I would imagine that when sending documents from the Teletype Model 33 to most other teleprinters (which I believe were the majority of teleprinters worldwide), the operator would have to ensure, or should have ensured, that the character line length did not exceed 69 characters, to prevent over-printing at the end of lines.

Teletex Was Much Faster Than Telex

Teletex terminals could send messages at much higher speeds than telex machines could. The transmission speed was 2,400 bits/sec, around thirty times faster than telex. Source: Information Technology Impact on the way of life. PDF file. Page 30.

Teletex System Specifications

Here is a link to a PDF file on ITU-T’s website that details the equipment specifications for using the teletex service. The link will automatically open a PDF file on your computer or other device you may be using.

Complete Listing of ITU-T Teletex System Specifications

F.200, T.60, T.61, T.62, and T.70. Source: Teletex: The brief abandoned step between Telex and Telefax. Fast forward the video to 5 minutes and 20 seconds to view that portion of the video.

If you would like to view each of these PDF documents, you can go ITU-T’s website Home Page and use their search facility by typing in one of the document specification numbers listed above.

Why Was The Teletex System Abandoned

At the time of the initial teletex system concept in the early 1980s, commercial electronic mail had already been developed and was being used by many companies worldwide. Source: Personal experience of the author in office environments. Group 3 and Group 4 fax machines had been established in 1980 and 1984, respectively. Source: Fax Communications at Britannica. I found that these digital fax machines could send a page of A4 text in less than one minute.

Crucially, however, in the 1990s, private email was already taking a foothold with home users, and email was also rapidly gaining popularity within commercial enterprises. This popularity and accessibility to email must have signalled the end for not only the teletex system but also the worldwide telex network.

External Links

Text link to Harald Welte’s video about teletex

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