USB-C color codes

The USB-C connector is gaining in popularity, but it is also increasingly difficult to figure out what a particular instance does. To solve this problem, I suggest a simple system: colour codes that indicate the nature of a particular port. Ports that support multiple protocols can have a multicoloured hatchings. In the highly improbable that a manufacturer ads some feature to an existing port – say with a firmware update – this can be fixed with some sticker.

Here are some proposed values, largely based on the PC System Design Guide.

Color Codes for USB-C connectors

Legacy USB /

USB 3.0

Power Delivery Specification

Display Port Alternate Mode

Thunderbolt Alternate Mode

HDMI Alternate Mode

Audio Accessory Mode

Maintenance /
Firmware update only

USB Attached SCSI


Serial Port Emulation

Parallel Port Emulation



The fact you cannot tell immediately which ones are serious and which ones are not, is part of the problem…

USB-C pinout without text Creative Commons CC0 1.0 Universal Public Domain Dedication

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.