[greggman]

Is that really true? (I have no idea just asking). Is there nothing you could put in the device to prevent bad inputs from damaging the internals? (for some definition of bad)

Is it a question of impossibility? Or cost? Or bulk? or something else?

[Bjartr]

I thttp://www.fiftythree.org/etherkiller/ttp://www.fiftythree.o... it's a matter of foreseeing the potential failure modes and correctly deciding which ones are so remote as to be not worth the cost and complexity to protect against. For instance, I don't think there's a consumer device out there that wouldn't fry if connected directly to mains AC through any peripheral port at all. But that doesn't stop someone from making a cable that connects AC to USB and saying it's a fast charge cable on Amazon. That's a more extreme case than this, but only because it's more obvious what the flaw in the cable is.

[Dylan16807]

A cable with a mains plug at one end and USB on the other is obviously wrong, though.

Mains power is legitimately difficult to deal with. Power that's five volts out of spec is not.

[sharpneli]

A cable that puts 5 volts into random pin is also obviously wrong.

It's a balancing act between the probable failure modes and the cost of replacing the broken devices. Hostile manufacturers is not common enough of a failure mode (vs just Amazon sending a replacement device) to accept the additional cost for every single unit made. It makes no sense to spend 1 dollar more per device if it saves 1 cents per device on average for replacement costs.

If this kind of issue becomes more common then it might make sense. But for now it doesn't seem likely.

[Dylan16807]

>A cable that puts 5 volts into random pin is also obviously wrong.

I mean that the physical object is obviously wrong. Such a cable looks like any other cable.

[qb45]

Just as a side note, some of the cheapest USB chargers have 1mm or so of clearance between high voltage and low voltage circuits, which places them one small accident away from the "mains to USB adapter cable" territory.

[Dylan16807]

I know, but that's not a cable. You need more diligence when buying transformers, but a wire with a plug shouldn't be able to do unexpected damage.

[Bjartr]

Sorry about the weird url problem. I typed this on my phone in the HN app and had tried pasting in a URL at the end of my text. After being seemingly unable to get the URL to show up after two tries I gave up and cut down my post to not talk about the URL. I seem to have somehow inadvertently double pasted said URL to the beginning of my post in the process of all that.