Some of the messaging systems on the railway are still known as the Telex or the Teleprinter by some of the more 'vintage' staff...
The teleprinter service on B.R. was called 'S.T.R.A.D.' but I can't remember what the letters stood for.
The STRAD typists typed from the manuscript you gave them. If they stopped input for a (quite short) time the call would be disconnected. To save this happening, when they came to the bit of your handwriting that took a while to interpret, they would flick their left ittle finger down to the 'a' key and keep it there until they were ready to start typing again. It meant hat when you received a STRAD message from someone with poor handwriting it might seem like the sender was in trouble

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My bit of B.R. was really cutting edge by 1990. If you wanted to contact a colleague 'out on the district' you phoned a number, told an input typist what the message was and who it was for, and their pager buzzed and the message appeared. Being a pager messaging typist must have been a very short lived career