HDMI
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.
LAN (RJ-45)
The presence
of a LAN connector (RJ-45) makes it possible for the card reader/hub to work as a LAN adapter.
This port is commonly used for wired connection to computer networks. This connection may be preferable to wireless in some situations, but some devices (such as ultra-thin laptops) may not have a native LAN port. And in a PC, where such a port is usually installed on the back of the case, it can be much more difficult to get to it than to the USB connector. For such cases, card readers / hubs with a built-in LAN adapter are designed — usually, these are external devices connected via USB and capable of operating as an external network card.
Cable length
The length of the cable supplied with the device. Mostly relevant for models with a non-removable cable that cannot be replaced.
