HDMI is the most popular of modern multimedia digital interfaces. It is specifically designed for HD content and provides the transmission of high-resolution video and multi-channel audio through a single cable.
HDMI outputs are mainly found in hubs connected via USB Type C and compatible with the Thunderbolt interface (see "Connection"). Essentially, to use HDMI, you will need to connect the device to a Thunderbolt v3 port — a "pure" USB Type C does not support video transmission. This capability may be useful if an external screen is intended for HDMI connection, but your PC or laptop lacks such ports, or they are occupied or unavailable for other reasons. HDMI can have different versions, which affects its bandwidth. For instance, to transmit 4K video at 60 fps, you need
HDMI v 2.0 or 2.1. And
multiple ports will allow you to connect more than one monitor.
External USB devices require power to work, which is supplied to them through the same USB port. However, the power of such power supply is relatively low (especially in version 2.0 ports, see "Connection"), and if several external devices are connected to one port of the computer through a hub, a situation may arise when the power is not enough for their operation.
Connecting an external power supply to the hub allows you to avoid such situations: the hub receives additional power from the network and supplies power of the appropriate power to each of its inputs.
Another option for using devices with this function is charging portable equipment via USB: some models can work as stand-alone chargers that do not require connection to a computer.
