Cable length
The length of the cable that the keyboard is equipped with for wired connection (see "Connection type").
When choosing this parameter, you should first of all take into account the distance from the device to the connection port: a cable that is too short may simply not reach the connector, and a cable that is too long may get confused at hand and create inconvenience. As for specific values, the reference length is 1.8 m. However, there are cables both shorter and longer.
Additional keys
The number of
additional keys provided in the design of the keyboard.
Such keys do not belong to the standard layout and are intended for quick access to specific functions or individual applications — for example, to control the media player or open mail with one click. This function is convenient because commands from additional keys are usually recognized by the system regardless of what is on the screen — thanks to this, for example, you do not have to close the text editor to switch tracks in the player.
Note that in this case we are talking about individual keys that have a strictly defined purpose and corresponding markings. Programmable buttons, the Fn key (see below) and the functions of the main keys implemented through Fn are not taken into account in this paragraph.
Interface
Interface used in a wired keyboard (see "Connection type").
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USB. A standard universal connector for connecting peripherals, present in almost all modern computers — from desktop PCs to microcomputers. USB keyboards are the most versatile, so this option is the most common today. The main disadvantage of this option is that the USB slot occupied by the keyboard may be needed for another peripheral device; however, this problem is quite easily solved — for example, using a USB hub or purchasing a keyboard with its own hub (see below).
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PS/2. A specialized connector with a characteristic round shape used to connect keyboards and mice; in modern PCs, both two ports can be provided, for both, and one universal. Anyway, this connection method is convenient in that all USB ports remain free; this can be important when using numerous USB peripherals. At the same time, the PS/2 connector itself is rather large and poorly suited for laptops and other compact equipment, and therefore is found only in desktop PCs. And even in the latter case, it's ok to check the availability of PS/2 before buying a keyboard with such a plug.
— USB or PS/2. Usually, in this case, we mean USB keyboards equipped with an adapter for a PS/2 port. Features of both interfaces are described above; here we note that this option is the most versatile, it allows you to choose the connection method depending
...on the situation. In addition, it is convenient because there are relatively few PS/2 models, and it can be easier to find a suitable USB keyboard equipped with an adapter. The adapters themselves are inexpensive and do not really affect the price of the device; of course, they are sold separately, but the kit is often the preferred option.
— Corporate. Connection using a specific connector, which does not apply to the standard (described above) interfaces and is mainly used in the technique of a certain brand, at best, in some third-party devices. This option can be very convenient for tablet accessories (see "By Direction").
