Telex

Switched network of teleprinters A Teletype Model 32 used for telex serviceTelex is a telecommunication system that allows text-based messages to be sent and received by teleprinter over telephone lines. The term "telex" may refer to the service, the network, the devices, or a message sent using these. Telex emerged in Germany in the 1930s and became a major method of sending text messages electronically between businesses in the post–World War II period. Its usage declined as the fax machine grew in popularity in the 1980s. The technology operates over the circuits of the public switched telephone network or by private lines, using binary signals encoded with the International Telegraph Alphabet No. 2 at a standard speed of 50 baud. Telex provided the first common medium for international record communications using standard signalling techniques as specified by the International Telecommunication Union (ITU). A key feature of telex was the "answerback" system, which allowed senders to confirm with a high degree of certainty that their message had been received by the correct recipient. Telex networks were established in many countries. In the United States, the American Telepho