I don't think anyone actually has one of these machines, but greenkeyer Mike Kley sent me a pdf of 5641S (ARPE description and adjustments).

So now in one day we have gone from wondering if the ARPE actually ever existed to having a photo, plus description and parts manuals. Ain't Teletype archeology fun!

I found this part of the description interesting/amusing

"The punch will operate at speeds up to 1000 opm when AC selection is used. At speeds above this figure, beating between shaft speed and the 60 cycle selecting current occurs which appears on the tape as errors. With DC control, the punch will operate up to 1500 opm, or higher if carefully adjusted. A movement of .178" is required at the point of power application. This is sufficient for perforating two tapes. A movement of .190" is required for perforating four tapes."

So - punching four tapes at once at over 200wpm... in 1950. Those Teletype engineers certainly were some clever lads....

Cheers,