How does the JBC (and clones) Soldering Station Sleep Mode Work?

[Astray]

Hello,
I'm trying to get a better understanding of the JBC and Aixun T3A/T420 cartridge type soldering stations connections and how they work to put the soldering iron into the sleep mode while it's connected to its stand.

I remember reading a post (or maybe watched a video) about it but I've been unable to find it again even after searching the forum and googling. There was a breakdown of all the connections to the handle from the stand and the main station.

What is electrically happening when the outer metal part of the handle connects to the stand? What kind of voltage, current, and/or signal is it sending back to the main station?

I would like to know this information to make it easier to modify my soldering station and out of curiosity's sake too.

Thanks!