Inside an Otis elevator button (with schematic)

It's always interesting to take a look at elevator components. Especially Otis components because of their iconic history. This is a fairly standard illuminated halo button that may be used by other elevator manufacturers too. A search on AliExpress for the keyword br27c will find similar buttons, but they may have different connections than this one. Usually 24V because that's a standard control voltage in industrial applications. I've just ordered a couple to look at. The electrical configuration of this button is odd, because it has a four pin connector, but only three pins are used. A different style of button has the LEDs and switch on four separate connections. It does make sense to use 3 wires though, as the switch signal is also 24V in some applications. If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- https://www.bigclive.com/coffee.htm This also keeps the channel independent of YouTube's algorithm quirks, allowing it to be a bit more dangerous and naughty. #ElectronicsCreators