I've heard about this awful thing but have never heard it demonstrated. This is so clearly a poorly thought out system bolted on top of hardware that was designed without a thought to our existence. Meanwhile, why not configure it so you press the button to scroll through floors, hold it to confirm, and just wait 15 seconds to cancel? It would cause a 15-second delay if you accidentally pressed the button too many times, but would otherwise be very efficient.
@simon @bmoore123 If you can't have a keypad because of space, you could maybe also have up/down arrows and a center button, press and hold to confirm, double press to cancel. Or if it's just one button, press once to advance, twice to go back, press and hold for one second to confirm, tripple press to cancel. And also it's distorted which garbles some of the floor numbers, that might just be a crappy speaker though.
@simon @bmoore123 But yeah, a keypad is the ideal option. Telephone-style, probably. Please select a floor and enter pound to confirm, star to cancel. ALl you then need is a message for not valid floor or this elevator doesn't go to this floor. Or maybe auto-confirm on two digits and have the first floors need you enter something like 01.