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I would imagine that a phone could also check for the E-Mark and limit charging power accordingly. (Presumably this is how USB-C already works, but maybe not.
by amluto 4y ago
I would imagine that a phone could also check for the E-Mark and limit charging power accordingly. (Presumably this is how USB-C already works, but maybe not. Certainly something tells the power sink the current limit, but I can imagine that the source queries the cable, computes (potentially incorrectly) the limit, and tells the sink, which then blindly trusts it.
- error503 4y agoThe 'DFP' (source) interrogates the cable, and when it advertises its capabilities to the 'UFP' (sink) it will only include what is mutually supported by the source and cable. In theory I believe the 'UFP' can also query the cable once in a contract, but not sure if this is common/ever done, I guess this capability mostly exists to inform the user if the cable they are using is insufficient.
- amluto 4y agoApple could implement that and refuse to charge quickly with an inappropriate cable. No special MFi chip needed
- yencabulator 4y agoThe MFi chip is "needed" for profit.