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I couldn't find any good videos of toggling in a bootloader on a real PDP-11, but here is one on a PiDP-11 emulator: https://www.youtube.com/watch?v=31vrju0BMQc

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well this is disappointing..."binary toggles" had me picturing a single 3-way toggle switch where you manually entered ones and zeroes.

That is exactly what is going on but you don't need 3 way toggle.

Down is 0 and up is 1, you load all of the values in like a shift register but in parallel, then write/act upon them.

Yes the data bits were 2-way toggles, but one important switch was a 3-way toggle: the Examine (press down) and Deposit (press up) switch.

On the 11/70, Deposit was the only switch that toggled up (other than the light test switch). That is a nice safety feature so you don't accidentally toggle Continue or other action switches.

Right...but surely you see how that's different from what I described.

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