i-tec USB-C Dual 4K/60Hz (single 8K/30Hz) HDMI Video Adapter

How do I recognise a USB 3.0, USB-C or Thunderbolt 3 port?

The first key difference is appearance. USB 3.0 is rectangular, usually with a blue plastic insert (may differ by manufacturer, however). USB-C and Thunderbolt 3 have an oval shape. Thunderbolt 3 is marked with a logo of a lightning bolt. The USB-C connector has no specific rules and can be marked in various ways (depending on the port's specific properties) or may carry no markings whatsoever. The port's specifications are listed in the manual of the laptop. In most cases, they can be found under the USB-C/Thunderbolt3 listing where the properties of the given port will be stated.

Here are some examples of how a Thunderbolt 3, USB-C and USB 3.0 port may be marked:

USB 3.0	Thunderbolt 3 vs. USB-C

Manuals are available on the website of the laptop's manufacturer.

How do I tell how many Watts my laptop needs?

This information can be found on the power supply which comes with the laptop. The value may be stated directly, e.g. 45 W, 65 W etc. Or can be derived through the equation W = U*I, where U = value in amperes (A), I = value in volts (V).

For example, if the power supply states: Output 20V/2.25A. Then the equation is 20V*2.25A = 45W

How do I tell whether my port is capable of video transmission?

The feature of native video transmission is also known as Display Port Alternate Mode. It is always supported for Thunderbolt 3 ports and is an optional function for USB-C ports. The technology must be implemented by the laptop's manufacturer, otherwise it will not be available.

Whether the USB-C port features Display Port Alternate Mode is listed in the manual for the laptop. In most cases, this can be found under the USB-C/Thunderbolt3 listing where the properties of the given port will be stated (often labelled "video transmission").

Manuals are available on the website of the laptop's manufacturer.