USB А
The number of USB inputs located on the case of the card reader or hub (see "Type"). The number of USB ports that you will have at your disposal after connecting the device depends on this parameter. "Pure" card readers and combined models, usually, have 1,
2 and even
3 USB inputs, while hubs have
4 or more ports.
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.
External power supply
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.
Power Delivery
The technology allows you to work at higher voltage, thereby increasing the transmitted power.
USB hubs with Power Dlivery can not only charge smartphones faster, but also power more power-hungry devices, such as laptops.
Cable length
The length of the cable supplied with the device. Mostly relevant for models with a non-removable cable that cannot be replaced.
Activity indicator
Light indicator, indicating that data is currently being exchanged between the memory card and the computer to which the card reader is connected. This allows you to avoid disconnecting the card reader during operation, which is fraught not only with data loss, but even damage to the device.
