Here's some useful information about Otis 8200KA push buttons. I had to dig pretty deeply and there was a lot of misinformation online. I finally found a really old Unitec catalog and a schematic I drew back in the 90s that clarified it for me. Hope it helps some of you guys.

8200KA1 - pc board, 28v, with 1 incand. lamp with jumper on JW1, hall button only
8200KA2 - pc board, 28v, with 1 incand. lamp without jumper on JW1, car button only
8200KA3 - pc board with 1 orange LED with jumper, hall button only
8200KA4 - pc board with 1 orange LED w/o jumper, car button only
Important note: The KA1 and KA2 are identical except for the JW1 jumper. Likewise, the KA3 and KA4 are identical except for the jumper. If you install a KA1 or KA3 (with jumper J1) in the car it can damage the microprocessor. If you install a KA2 or KA4 (no jumper), I think the light will not work. In my experience, JW2 is always present on all of these Otis buttons.

By the way, Mathis Electronics has a replacement board that can replace all 4 of these boards.