Re:Apple rumored to subvert EU Rules by nerfing USB-C on iPh...
by arcticbull on Wednesday March 01, 2023 @04:09PM
(#34988386)
The is an incomplete assessment because the cable itself plays an active role here via USB-IF required electronic marker. [1]
Not all cables have suitable internal wiring or receptacles capable of handling either higher voltage or amperage required. The ability to transmit 60W or 100W was a much later addition to the specification. In fact USB-C PD 3.1 / EPR supports 240W (48V at 5A) as of much more recently.
This is why the in-cable e-marker was added to the specification: so the cable could indicate whether it was designed to handle higher voltages and currents without catching fire.
In modern USB-C power delivery, it is the source, the sink and the cable that determine how much power is supplied.
Not all cables have suitable internal wiring or receptacles capable of handling either higher voltage or amperage required. The ability to transmit 60W or 100W was a much later addition to the specification. In fact USB-C PD 3.1 / EPR supports 240W (48V at 5A) as of much more recently.
This is why the in-cable e-marker was added to the specification: so the cable could indicate whether it was designed to handle higher voltages and currents without catching fire.
In modern USB-C power delivery, it is the source, the sink and the cable that determine how much power is supplied.
[1] https://web.archive.org/web/20170816061107/http://www.usb.or... (p. 42)