It isn’t an AT-400, so I guess an IMotion? It doesn’t have a discernible model name, just a series of numbers that don’t see to tie to any particular United/Otis door operator when googled.
Two pulleys and a dolor arm, 2001 era, pulleys are read by optical sensors, a motor and a blue box with a red digital readout and “up, down, enter” buttons. I have pictures but am not sure how to post them.
Went ahead and played with a “setup” command and got all the way to a “learn run” when it said, “WARNING, E-Stop ignored, Enter to continue or _____ to quit.” So I quit, not knowing what E-stop meant!

I need a manual that instructs on physical setup AND digital adjustment. I’m pretty sure someone has either messed with the adjustments or loose bolts allowed them to shift - there is evidence of wildly different settings on some of the sliding and slotted physical adjustments.