All-caps typewriters were also used by Western Union for telegrams that were phoned in, and

probably before that for Morse reception.  Also used by radiotelegraph companies for the high

speed Morse (up to 500 wpm or so by radio) that was received on ink recorders and transcribed

by typists.  And there were Army radio sets in shelters that used CW prior to radioteletype.

 

The Western Union typewriters looked like ordinary commercial typewriters of the period except

that the metal front panel was red rather than black.  I'm only speculating that this was intended

to distinguish company-owned typewriters from those owned by the individual telegraph operators.

Apparently typewriters were marketed to telegraph operators as individuals when they wanted

to copy easier and faster than they could do by handwriting.