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.
USB cable compartment
A special compartment on the case of the card reader or hub (see "Type"), in which the USB cable is placed during non-working hours. Such models are compact and easy to transport due to the fact that the wire, which tends to get confused and interfere, is hidden inside the device. For objective reasons, only devices with an external connection can have
a cable compartment(see "Intended use").
Removable USB cable
The ability to disconnect the cable from the device through which it is connected to the USB port of the computer (see "Connection"). This gives a certain convenience during transportation — a
removable cable is somewhat easier to lay than a non-removable cable, you can carry it separately, etc. In addition, it becomes possible to replace the cable — for example, if the regular cable is not long enough, or if it is damaged.
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.
