Telex

Telex (pronounced tel-eks)

(1) A two-way teletypewriter service channeled through a public telecommunications system for instantaneous, direct communication between subscribers at remote locations (sometimes with initial capital letter).

(2) A physical teletypewriter machine used to send or receive on such a service.

(3) A message transmitted by telex.

(4) To transmit such a message.

1932:  A compound coined word to describe "a communication system of teletypewriters", the construct being tel(eprinter) + ex(change).

The Telex

Although most associated with the clunky looking teleprinters used to type and send/receive messages, telex actually refers to the network over which the message traffic passed.  Point-to-point messaging like the telegraph long pre-dated the telex network and, being based on physical wires and cables, introduced into English the verbal shorthand for such messages: the wire and the cable.  Teleprinters evolved from the telegraph, both using binary signals, best understood by reference to Morse-code in that symbols were represented by the on/off of an electrical current.  Because this is so different from the variable voltage model of analog telephone systems, the telex network was wholly separate.

Slovenian news site, telex.si. 

The first telex network was built in Germany as a university research project in the later years of the Weimar Republic, the first commercial services being offered by the Reichspost (German post office) in 1932.  Adoption was slow until the post-war years but telex become widely popular after 1945 and by the 1960s was the de-facto standard for long-distance corporate communications.  It was a robust and high-security network with both error-checking for the message and a machine-2-machine answerback protocol under which the sending machine sent a WRU (WhoaReyoU) code to which the recipient machine would respond with the transmission of an unambiguous identifying code.  It meant it was difficult to send a message to an incorrect address; something a few eMail and Twitter users might wish existed on their systems.

Still a niche market.  

Telex is used now only by those prepared to pay the cost for very high security.  Although still available from swisstelex in some western European countries, telex is now almost entirely a relic except for niches like underground military installations or TvHF (telex via HF radio) which remains a required element of the Global Maritime Distress and Safety System.  Telex generally went into decline as services like fax, eMail and SMS because ubiquitous.  These innovations, although technically much different for telex, were, to the users, lineal descendants, inheriting particularly the stylistic techniques of abbreviated English such as CUL8R or FYEO which the Nokia generation of the 1990s claimed as their invention.  Except for the swisstelex service, vendors offering telex emulation across various platforms do so without dedicated lines.