Sunday, July 02, 2017

[ysthrihy] Data then power

It is easy to imagine, but hard to implement, a protocol in which when something gets plugged into a power source, e.g., a wall outlet, first some low power low voltage data communication happens between the outlet and the device that establishes what kind and how much power the device wants, then it switches over to power mode delivering that power.

The initial communication can also establish that it is actually a device plugged into the socket, and not a kid sticking their finger into an outlet.  For example, the outlet could ask the device to solve a new randomly generated puzzle.

The difficulty in implementation is that the low power data processing equipment must be connected to something which will eventually also transmit high (mains) voltage and amperage.  We might trust an electromechanical switch with a large gap to isolate it when switched over to power mode, but worry that anything small and solid state might arc.

How many wires are strictly necessary to transmit data?  USB uses four, but I suspect Morse code was transmitted over just 2.

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