During my weekly golf outing this past Sunday, someone made this quip about the olde tyme telegraph as their ball was rolling towards the hole, “roll roll roll STOP I said STOP STOP” or something to that effect. To which my other golfing partner said, “why did they say STOP? Wouldn’t it have been easier to just use a period?” (or maybe I’m making that last part up as a transition tool… I can’t remember).
Way back when, if you were sending a telegraph, you got a large number of words included in your fee. Punctuation, however, was extra. So, instead of using periods, they had the operators just type STOP.