what is telex message

The telex network is a switched network of teleprinters similar to a telephone network, for the purposes of sending text-based messages. The term refers to the network, not the teleprinters; point-to-point teleprinter systems had been in use long before telex exchanges were formed starting in the 1930s. Teleprinters evolved from telegraph systems, and like the telegraph they used the presence or absence of a pre-defined level of current to represent the mark or space symbols. This is as opposed to the analog telephone system, which used differing voltages to encode frequency information. For this reason, telex exchanges were entirely separate from the phone system, with their own signalling standards, exchanges and system of "telex numbers" (the analog of a phone number). When telephone and telex exchange equipment was co-located, which was not uncommon, the different signalling systems would sometimes cause interference.

Telex provided the first common medium for international record communications using standard signalling techniques and operating criteria as specified by the International Telecommunication Union. Customers on any telex exchange could deliver messages to any other, around the world. To lower line usage, telex messages were normally first encoded onto paper tape and then read into the line as quickly as possible. The system normally delivered Baudot-encoded information at 50 baud or 66 words per minute. In the late days of the telex networks, end-user equipment was often replaced by modems and phone lines as well, reducing the telex network to what was effectively a directory service running on the phone network.