bobvan

I think the key to understanding this filing is in the wiring guide.

First, it has an RS485 interface. Serial. Probably only kilobits at most.

Second, it takes a very wide range of voltages from 5 to 13 V. That means the power isn't coming from Apple. If they were building the power supply, they'd know it was 7.5V, or 9V, or 12V, or whatever.

Third, the power consumption is low, typically 1 Watt. So you know there's no GPU. And no top-end CPU. Think of the energy budget you have with a battery powered device, except we know that this uses wired power instead. And you'd probably want more like at least 5 Watts for wireless charging or it'd take forever.

So somebody else is building the power supply, it only needs 1W on average, and it has serial and radio connectivity.

A charger would have USB or maybe just DC power, so I think a charger is highly unlikely. And Mike's right, don't worry about radio. Passes right through you harmlessly or people who live near radio and TV station transmitter sites would all be mutants.

My money is on a contactless payment device. This would sit on the checkout counter next to a payment terminal that would provide the power and receive the payment information via the serial connection. Apple would want to interface with a variety of different payment terminal vendors with a wide range of power supplies, hence the wide voltage range. It doesn't take a GPU or high-power CPU to run the crypto and other payment approval work. And a puck shape is a perfect spot for an Apple Pay logo to be prominently displayed on the checkout counter.

It's been 4 years since I was in Japan, but back then, every newsstand there had these nice little "Passmo" pucks sitting the counter. You just picked up an item from the store, flashed the barcode, and tapped your Passmo contactless payment card and you were done.