USB-C plugs either way — why do some cables only charge and never copy files?

Question

Weirdo · Accepted Answer

The USB-C plug shape is not a full SuperSpeed cable. USB-IF splits USB 2.0 Type-C cables from full-featured ones; the former have no TX/RX pairs and top out at 480 Mbps. Some charge-only cables omit even D+/D- and wire only VBUS, GND, and CC, so they power a phone and carry no files.

USB-IF is blunt: USB Type-C is a connector specification, not USB 3.2 or USB4. Reversible plug orientation only means the shell is symmetrical. It does not mean SuperSpeed pairs are inside. A USB 2.0 Type-C cable “physically cannot support USB 3.2 nor USB4 signals”; TX/RX and Alt Mode (SBU) lines are not implemented. It is meant for USB 2.0, 480 Mbps. Fast file copy needs a host, a device, and a full-featured USB Type-C cable.

Benson Leung, reading USB Type-C spec 1.4, lists several C-to-C kinds: USB 2.0 at 3 A or 5 A, and full-featured cables that add ten SuperSpeed wires. The spec does not force every cable to carry every wire, because that would explode cost for charging-first use. Cheaper charge-only cables may drop even the USB 2.0 D+/D- pair and leave VBUS, ground, and CC for power-role talk. Same shell, different copper.

USB-C plugs either way — why do some cables only charge and never copy files?

Fitting the port does not mean the wires are all there

A charge-only cable may skip the data pair entirely