Comparison Logitech Wireless Keyboard K270 vs A4Tech KV-300H

— Wired. Connection using a cable with one or another type of connector — most often USB, less often PS/2 or a proprietary plug (see "Connection interface"). Wired keyboards are notable for their low cost and overall convenience — in the sense that they do not require batteries and the operating time is unlimited. However the wire limits mobility; however, given that most often the keyboard is used in close proximity to the computer, this shortcoming cannot be called critical.

— Radio. Wireless connection over the air, usually through a wireless adapter connected to a computer via a USB port. The main advantage of this option can be called the actual absence of a wire; while the communication range is usually several metres, which gives freedom of movement and even allows you to use the keyboard as a "computer remote control". On the other hand, wireless models are much more expensive than wired ones, and their operation requires separate power supply from batteries or a rechargeable battery, the charge of which is limited — accordingly, the continuous operation time is limited. Separately, we note that this option is designed mainly for stationary PCs; if a wireless keyboard is needed for a laptop, it is better to pay attention to Bluetooth models (see below).

— Bluetooth. Another way to wir...elessly connect keyboards. Technically, Bluetooth is based on radio waves, but this technology has its own characteristics, so it is listed separately from the "normal" radio connection (see above). The main one of these features is that many models of modern electronics (almost all laptops and tablets, some PCs, etc.) are equipped with built-in Bluetooth modules, which allows you to connect such keyboards without using additional adapters. In addition, the range of such a connection is officially at least 10 m (in fact, of course, it depends on obstacles, interference, etc.). It is this option that will be optimal if you need a wireless keyboard for a Bluetooth-enabled device.

— Bluetooth / radio. Wireless keyboards that can connect both via Bluetooth and radio. See above for more details on each of these options. Also note here that such a keyboard is usually connected directly to a Bluetooth device (for example, a laptop), and if the computer does not support Bluetooth, you can connect a USB adapter to it and use a radio connection. Thus, the keyboard is as versatile as possible in connection. However, such versatility significantly affects the cost, and is required not so often; so this option is not widely used.

— Bluetooth / radio / wired. Keyboards that support all three connection methods described above. This is the most versatile option, giving the user the freedom to choose for different situations. For example, while playing a game or watching a movie, you can sit in a comfortable chair away from the screen by connecting the device wirelessly, and when typing or surfing the Internet, you can move to the table and use the wire, saving battery power. At the same time, such versatility is not often required and is expensive, so models with this type of connection are not popular either.

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.

The wireless connection range provided by the keyboard (see "Connection type").

Almost all modern wireless models function reliably at a distance of at least 2-3 meters. Therefore, you only need to pay attention to this parameter if the keyboard will be used farther from the computer. When evaluating the range, keep in mind that it is given for ideal conditions: no interference or obstacles, a fully charged battery, etc. In practice, the actual range might be somewhat shorter, so it's advisable to account for a margin when selecting a model. Nevertheless, the stated range can give a good indication of the practical capabilities of different models and help in comparing them.

— Classic type. Keyboard with keys of the usual square and rectangular shape, with a small distance between them. Such keys usually expand downwards so that the gaps between them are as small as possible.

— Island type. Also known as "soaring" or chiclet. This is a keyboard in which each key is installed in a separate hole at a small distance from the others. Island models are more convenient than classical ones in that they are less likely to accidentally press the adjacent key. On the other hand, they are more difficult to clean: debris that has clogged into the gap between the key and the “board” itself is quite difficult to clean out, while contamination can create problems in operation.

On the practical side, the choice of a particular type of keys depends primarily on the personal preferences of the user.

— Membrane. The name of this type is due to the fact that the contacts under each key are made in the form of two membranes — conductive disks on a flexible film. The return of the keys to their original position after pressing is ensured by the elasticity of the membranes. This design is characterized by low cost and low noise level; in addition, such keyboards are quite resistant to liquid spills (although this is still not recommended). Of the shortcomings, it is worth noting the relatively low durability — 3-4 times lower than that of mechanical ones. In addition, as the keys of this type wear out, the force required to press decreases, they begin to “fall through” under the fingers (“fatigue effect”).

— Mechanical. In this design, springs are used to return the key to its original position after being pressed. Mechanical keyboards are considered more advanced than membrane keyboards: they are more reliable and durable, almost do not lose properties as they wear out, and give a clear tactile feedback. The overall noise level is often higher than that of membrane ones, however, many attribute a characteristic click with each press to the advantages of such models; in addition, completely silent mechanical switches are also available. But of the unequivocal disadvantages, one can name the high cost and sensitivity to spilling liquid (although a mechanical keyboard can also be made waterproof)....r>
— Optical-mechanical. A variation of the mechanical keyboards described above, in which each key is equipped not with a traditional pair of contacts, but with an optical switch in the form of a sensor that receives an infrared beam; when you press the key, this beam is blocked, which serves as a signal for operation. One of the key advantages of such switches is a very high response speed (fractions of a millisecond); this moment is not critical for domestic use, but it can be fundamental for gamers-enthusiasts and e-sportsmen. In addition, the absence of electrical contacts that are prone to wear and oxidize has a positive effect on durability. And although initially the “optics” are more complicated than classic systems with contacts, however, in gaming keyboards, optical-mechanical switches are often even cheaper than pure “mechanics”. And the fact that this option is relatively rare is primarily due to the fact that optical technology appeared not so long ago and is only gaining popularity.

— Membrane + mechanical. A layout in which most of the keys have a membrane design, and some, the most "responsible" ones, are mechanical. About the features of both options, see above, and a similar combination of them is found mainly in gaming keyboards. In this case, the "mechanics" are usually used on the traditional combination of WASD plus on the surrounding keys Q, E, R and F.

— Mechanical-membrane. A hybrid design that combines elements of mechanical and membrane keyboards (see above for more on both). In this case, these features are combined in each individual key. Usually, under each button in such keyboards there is a membrane, however, inside this membrane is not just a pair of contacts, but a mechanical spring system. Thus, this design combines the advantages of both options. At the same time, mechanical-membrane systems are very expensive. Therefore, their main scope is high-end gaming keyboards, and even among such devices this option is quite rare.

— Scissor. A slightly modified version of membrane keyboards (see the relevant paragraph), in which the flexible membrane on each key is supplemented by a two-piece mechanism fastened together in the form of scissors. One of the main features of scissor keyboards is the low key travel (noticeably lower than that of membrane keyboards). Also, this design is less demanding on accuracy, it allows you to achieve a clear pressing regardless of where the finger hit — in the centre or on the edge of the key. The service life of the "scissors" is large; they are more difficult to clean, however, they become dirty much more slowly than "membranes". Among the disadvantages of this option, a slightly increased noise level during operation can be noted — due to the clicking of scissor mechanisms.

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.

Volume control methodprovided in the keyboard (if such a possibility is provided at all).

— Through Fn. Adjustment using the Fn key (see above): increasing and decreasing the volume is carried out by simultaneously pressing Fn and one of the main keys of the keyboard (usually from the F1 — F12 row), The main advantage of this control is that it allows you not to overload the keyboard with additional controls — this, in turn, has a positive effect on the dimensions and cost. The disadvantage is the need to simultaneously press two keys, which is not always convenient.

— Additional keys. Control with additional keys specially designed for working with volume. A very convenient and practical option: additional keys are usually clearly labeled, while they take up less space and are cheaper than a wheel or a touch slider (see below).

— Wheel. Control by means of a mechanical wheel, the rotation of which up and down or left and right provides a change in volume. A fairly user-friendly option — visual, intuitive and accessible even blindly. At the same time, the wheel can take up quite a lot of space, and it significantly affects the cost of the keyboard.

— Touch slider. Management using a touch surface, the movement of a finger in one direction or another. The sensor takes up minimal space, looks neat...and generally fits well with the overall design of the keyboard, but it is not cheap. Therefore, this option is extremely rare, mainly in high-end gaming or multimedia keyboards.

The number of native USB ports in the keyboard design.

The presence of these ports actually allows you to use the keyboard as a USB hub — for connecting various peripherals to a computer. Such a connection is convenient because the connectors are literally at hand, you do not need to reach for the system unit. The number of ports corresponds to the number of USB devices that can be connected to the keyboard at the same time without the use of splitters and other additional equipment.

The type of power used in wireless keyboards. It can be a replaceable battery or its own built-in battery.

As replaceable batteries in modern keyboards, batteries or accumulators of the AA (“finger”) or AAA (“mini-finger”) format can be used. The main advantage of this power supply is the ability to quickly replace dead batteries with new ones — if there are any left, a few seconds are enough, and the keyboard is ready to work again. However, batteries are often not included and must be purchased separately. In addition, anyway, you have to buy new batteries as the old ones wear out — or fork out for rather expensive batteries and, possibly, a charger.

Built-in battery, in turn, relieves the user of the need to purchase batteries. On the other hand, in the event of a discharge, such a battery cannot be quickly replaced, and the only option to continue working is to charge it, which can take quite a long time.