Interface
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USB A. A classic, mainstream USB port that has recently been losing ground to the more advanced USB-C port.
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USB-C. This connector differs from the classic, full-sized USB in much smaller dimensions, as well as a two-sided design that allows you to insert the plug in either direction. This interface is rarely found in desktop PCs, but is becoming increasingly popular in laptops, tablets, and phones. Note that the Type C standard only describes the connector design; The USB version (interface) is described in the paragraph below.
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Lightning. Apple's proprietary interface used in its compact devices (iPhone, iPad, and iPod touch) since 2012. In terms of application features, it is completely similar to the microUSB described above, adjusted for the fact that it is found only in “apple” gadgets and is not used by other manufacturers.
— Internal USB. A variation of the USB standard used to connect internal card readers (see "Type", "Destination"). It differs from external USB in a connector; you can connect a card reader with such a connection only to the connectors on the motherboard; it is not compatible with external USB ports. Other characteristics are completely similar to the corresponding external USB standard (see above).
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microUSB. A reduced version of the external USB interface (see a
...bove): the dimensions of such a connector are several times smaller than those of a full-sized one, which allows it to be used in portable equipment, in particular smartphones and tablets. Actually, card readers and hubs that use this interface to connect are usually designed for such equipment. Note that normal operation is possible only if the main device is capable of operating in USB host mode (this function is called USB On-the-Go).
— Wi-Fi. A wireless standard originally developed as a technology for building computer networks; later, Wi-Fi Direct technology appeared, which allows you to connect devices directly to each other. In card readers and hubs, this technology is found mainly among models designed for use with mobile devices (laptops, smartphones, tablets) that have a built-in Wi-Fi module. At the same time, the advantage over wired interfaces is not only the absence of wires and the corresponding freedom of movement, but also the possibility of simultaneously connecting several devices and exchanging data with them. And some models with Wi-Fi can even be connected to computer networks as full-fledged network drives. Of the shortcomings, it is worth noting the need for its own power source — either connecting to the network, which accordingly limits freedom of movement, or a battery that has a limited battery life (within a few hours).
— ExpressCard. A standard for connecting compact peripherals, mainly used in laptops. ExpressCard devices are usually 75x34x5 mm in size and are installed in a special slot in the computer case. Depending on the features of the system, it can provide speeds up to 2.5 Gbps, but in general it is less versatile and convenient than USB, due to which it is much less common and continues to lose popularity. Found exclusively in card readers (see "Type").
— Corporate outlet. Connecting external card readers (see "Intended use") through the original connector, which is usually used in the technique of a single manufacturer and does not comply with common standards like USB (see above). The scope of such models is quite limited, most often they are produced as additional accessories for certain models of portable equipment (for example, tablets).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.
Card slots
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SD(from Secure Digital). One of the most common modern memory card standards, widely used in photo and video equipment, laptops, tablets, etc. The media has a size of 32x24x2.1 mm. A design feature is mechanical write protection in the form of a slider (however, its correct operation depends on the functions of the card reader, and not on the card itself). Support password protection and DRM technology. To date, there are three generations of cards of this standard: the original SD (up to 4 GB), SD HC (up to 32 GB) and SD XC (theoretically — up to 2 TB). Their physical size is identical, and the card readers support earlier generations, except for the main one. So, the device under SD HC will “understand” the original SD, and the reader under SD XC reads all three generations. At the same time, a "later" card will not be able to be read correctly by an "earlier" card reader.
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miniSD. Smaller version of SD cards (see above). It is identical to them in almost everything, except for the size (22x20x1.4) and write protection, due to which it can also be read in SD-card readers when using a special adapter.
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microSD. Another smaller version of the SD standard, 15x11x1 mm in size. Almost completely identical to the original, except for the dimensions and write protection. Due to its compactness, it has become widespread in portable technology, especially mo
...bile phones. It can also be used in SD card readers when using an adapter, and in some models even without it. — CompactFlash. This standard appeared one of the first and has survived to this day in a slightly modified form due to its good capacity (up to 512 GB) and high write speed — which is especially important in professional digital photography and video filming, where these cards are still quite widely used. The disadvantage is significant dimensions: 42x36 mm with a thickness of 5 mm (CompactFlash Type I) or 3.3 mm (CompactFlash Type II). The compatibility of both types in fact is directly related to the size: the Type II card simply won't fit in the Type I reader, but vice versa is quite possible. In addition, Type I and Type II differ in speed.
— XQD. A format developed by the CompactFlash Association as a potential replacement for CompactFlash and intended for devices with high requirements for read and write speeds. Actually, the data exchange speed, depending on the version, can reach 1 GB / s in the original XQD and 2 GB / s in cards supporting the CFexpress standard, with the prospect of further increase to 8 GB / s and even higher. At the same time, the cards themselves turned out to be smaller than СompactFlash, although they are still quite large — 39 x 30 mm with a thickness of 3.8 mm.
— MemoryStick. Sony's proprietary memory card format is used primarily in its devices, such as camcorders and handheld consoles. Such cards have a size of 50x21.5x2.8 mm (original version) or 31x20x1.6 (various Duo modifications), and the volume can reach 32 GB. Although cards are produced not only by Sony, the standard is officially closed, and therefore only cards of the original production can be guaranteed to comply with it.
— Memory Stick Micro (M2). A smaller version of Memory Stick cards (see above), have dimensions of 15x12.5x1.2 mm and a capacity of up to 32 GB. Compatible with readers for original Memory Stick using special adapters.
— xD-Picture. A specialized format jointly developed by Olympus and Fujifilm for their own digital cameras. They are distinguished by the absence of their own memory controller, which, on the one hand, ensures compactness and reliability, on the other hand, reduces performance. In addition, according to Olympus, using this card allows you to work with some of the camera's own effects. The theoretical volume of such cards is up to 8 GB. Another disadvantage is their high price. Due to this, xD-Picture is used quite rarely, and even manufacturers themselves transfer their products to other standards.
— MMC. Universal memory cards, similar in size to SD — up to the point that they are compatible with SD readers, and on some modern devices (cameras, camcorders, laptops ...) "SD / MMC" is directly indicated. At the same time, SD cards simply won't fit in MMC card readers. MMCs have low power consumption, but are expensive and not very fast in operation. Their maximum volume is 4 GB.
— MMC micro. A smaller version of MMC standard cards (see above) — they have dimensions of 12x14x1.1 mm, otherwise they are almost identical.
— cfexpress. Incredibly fast high-capacity drives with an eye for long continuous recording in intensive mode. They are the best suited for shooting video in 4K resolution and higher with a frame rate of 120 fps. So far, they are not so common in photo and video equipment. There are two types of CFexpress drives: Type A with dimensions of 20x28x2.8 mm and Type B with dimensions of 38.5x29.8x3.8 mm.
— SIM cards. Ability to use a card reader to work with SIM-cards used in mobile phones. In modern mobile phones, the SIM card is responsible not only for the number on the network — it can store a lot of different information, such as contacts, messages, settings profiles, etc.; as a result, the loss of a SIM due to loss or theft can turn into serious difficulties. The SIM card reader is designed primarily for such situations: with its help, you can save a backup copy of the data from the SIM card on a computer or external media, and later, if necessary, restore them without any problems.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.
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.