Teletype, telex or TTY: What is it, what is it for and how does it work?

This German device had its heyday at the end of 1945 and gained wide acceptance in European government postal companies due to the practicality of the implementation of this system.

In this article, We will show you what a telex is and what it is for. In addition, we will talk about its origin and evolution to the present day and we will tell you who are the people who use this tool today.

We bring you all the information you need to know about a TTY. Continue reading until the end of this article and you will find out all the details.

What is a teletypewriter or TTY and what are these devices for?

TTY or teletype is a device similar to a typewriter. It has an alphanumeric keyboard that manages to write messages for later sending. It also allows receiving typed messages from point to point, linked by a telegraph cable for later printing.

The most modern models use a screen, on which telephone communications can be printed. Currently this mechanism is obsolete, but it is used by people who have hearing problems so that they can obtain the telephone conversation in printed form.

Source

This device telegraphic has its origin in Germany, in the mid-20s of the last century. It was used for the Reich postal service with which a little more than 60 words per minute could be transmitted. After the end of World War II it was possible to expand to the whole world.

After more than 50 years of its creationthe postal services of the main European governments initiated shortwave radio links, the standard being “R.44”belonging to “ITU Telecommunication Standardization Sector”. Where the data transmission was done by a division in time according to time slots in a cyclical way, generating as a result a set of bits.

The communication system was done through direct current. Where it is interrupted in a very similar way to the dialing of a fixed telephone, using a point for the beginning and a line for the space, ending again with a point to be able to define a cycle.

evolution and history

Most of these teletypes used the 5-bit code (called Baudot or ITA2)which had as a limit 32 characters. Where, to enter some numbers special characters, exclusive keys for these should be used.

At first the computers used a bit for starting and stopping, due to its electromechanical design. As time went by, the devices became synchronous, often making the task of synchronizing their mechanical components difficult.

Therefore, it was decided to continue using the 5-bit Baudot code.where special versions were created to be able to apply them in certain reports, such as the meteorological ones.

The postal and telegraph services that did not have great economic resources carried out their operations in TOR or telex channels-Radio to get a higher value from them. In this way, with the passage of time, the cost of these equipments decreased considerably and as of 2016 people who are radio amateurs use this short wave system known as RTTY.

How does a telex work to send and receive typed messages?

These equipments they have a keyboard to write and a receiving device that is used to print the receipt of messages. Which are made through printed characters defined by electrical signals, which consist of different combinations of electrical impulses, both positive or negative.

In this way, different characters are sent and are interrupted according to a predetermined encryption by some standard. It is a system very similar to a fixed telephone dialing. Once the characters have arrived at the receiving telex, it starts printing them according to the standards assignment.

Telex vs Fax Which is better and how is each one different?

While is true that both devices have a similar physical appearance (considering the latest teletypes, since they were large and heavy in their early days)the technological difference that exists in each of them is very large.

As with telex you can send and receive messages via an integrated keyboardwhile with a fax also, there is a messaging service, but images can be incorporated that the first mechanical equipment does not support.

In addition, the texts that are generated in the fax are not created in the same device, but a separate text computer is needed to obtain a written message.

In this way, we can conclude that a fax is much better at present for sending and receiving messages than a telex is. This is because, not only can you send or receive texts, but you can also send different images or forms of drawings that can be digitized with special software and sent by email.