Card reader

How do card readers work?

A card reader allows you to connect memory cards to your device and is a kind of adapter that is interposed. Card readers of an SD card are probably the most commonly used, as well as card readers for CF Express (Compact Flash memory card), which are often faster and used in digital photography.

A distinction is made between external card readers with USB ports and internal fixed ones, which are not necessarily faster, but smaller. There are also single card readers (usually SD card readers), multi card readers (use of different memory formats) and series card readers (simultaneous transfer of the same type of memory). Single card readers are offered in a wide range by most manufacturers, as are multi-card readers, whereas series card readers are mainly used in the professional sector.

Depending on the number of available slots, as well as supported memory formats and whether or not it is possible to read and write simultaneously from more than one memory card, the products are divided into different categories.

What card readers are available?

Card Reader SD Card: SDHC (up to 32GB) and SDXC (64GB and above) can be inserted into card reader SD card, with reading and writing speed from UHS-I (100MB/s), UHS-II (312MB/s ) to UHS-III (up to 634MB/s)

Card reader XQD cards: XQD's use a PCI-Express interface and are offered up to 256GB. Read and write speeds of 400MB/s are possible. Card readers with USB are available for these cards from Sony, mostly as multi card readers. Cards and readers are much more expensive compared to the common SD format.

Card reader CF Express: Sony is the largest supplier of card readers CF Express together with SanDisk. There are card readers with USB B or C, as single or multi card readers. CF Express cards also use the PCI Express interface, and a distinction is made between Type A, B and C cards according to size, as well as read and write speeds of 1000, 2000 and 4000 MB/s respectively. These powerful cards and card readers CF Express are used in the professional field.

Reader for hard drives & SSDs: Readers in this category can be used to read hard drives via USB connection. Here the devices differ again in the type of USB port and its standard and in the maximum read and write speed.

What does 3 in 1 or 5 in 1 mean?

The specifications refer to the number of different memory types that the card reader offers you, they are always multi card readers, with more than one slot. 3 in 1 means that 3 different memory types can be used with one reader, with the majority offering the most common formats SD and microSD, as well as Flash. 5 in 1 means accordingly that five different types are integrated and so on. Some brands offer real jack-of-all-trades, such as 35 in 1 models offered by Hama.

Differences in the USB connection of the card readers

Card readers with USB ports offer different transmission standards, that is, primarily different speeds. First of all, the ports are divided according to their form into USB A, USB B and USB C, of which several subtypes are installed in mini and micro format. Within these USB types, the USB standards vary, i.e. the actual transfer speed of the connection. While the now obsolete USB 2.0 reaches its maximum at about 480MB/s, the newer USB 3.0 ensures a multiple of transfer speed with about 4GB/s. USB 3.1 represents a doubling of speed compared to USB 3.0 to 10GB/s gross and USB 3.2 is said to be capable of 20GB/s. Accordingly, newer standards represent the more suitable choice for fast exchange of large amounts of data. The end device to which the card reader is to be connected via USB must of course also have the high USB standard to enable this performance. So make sure that your card reader has the right port for the device you are using!