Comparison Logitech Corded Keyboard K280e vs A4Tech KV-300H

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.

Traditional keyboards are divided into three main varieties — full-size, compact and ultra-compact. The main difference between them is that full-size models have a Numpad — an additional block with numeric keys and arithmetic signs. Compact models, respectively, do not have a numpad, and in ultra-compact models, the arrow block is either completely absent or located under the Enter key in the form of very small keys.

And full-size, and compact, and ultra-compact keyboards can have different types of layouts. At the same time, the arrangement of letters and numbers above the letters in all types of layouts is the same, the differences are in the shape and position of additional keys (special characters like backslash, system control, modifiers like Shift and Alt, etc.). Here are the most popular options:

— ANSI. The "American" layout format, the distinguishing features of which are, in particular, the same width of both Shift keys, the same labeling and assignment of the Alt keys, the single-row Enter key and the backslash located above it (which is often made slightly longer than the standard key).

— ISO. "European" layout format. The Enter key occupies two rows, while at the top it is slightly longer than at the bottom; the left Shift is shorter than the right one, there is a...backslash next to it; next to the bottom of the Enter may be a second backslash or other special character key; the right Alt is designated as Alt Gr and is intended for entering additional characters in European languages.

— K.S. The "Korean" keyboard layout provides a double-row Enter, as in the ISO described above, however, in this case, the lower part of the Enter is made longer, and not the upper one. The backslash is above Enter, next to Backspace, and Backspace itself is the same length as standard keys (that is, noticeably shorter than in other layouts).

— JIS. Keyboards with a "Japanese" layout have a double-row Enter with an increased length of the upper half — like the ISO described above. However, in this case, the backslash is not located on the left side of the keyboard, but on the right, next to Enter (where an additional symbol key can be located in ISO). Additional character keys may be provided — next to Backspace (as in KS) and/or to the left of the right Shift. In addition, the right Alt can be formatted as Alt Gr.

In addition to compact and full-size, there are also non-traditional keyboard formats:

— Numpad. Separately made block of numeric keys. With the help of such a device, you can, in particular, turn a compact keyboard into a full-size one. Among other things, this combination can be useful for travel: packing a Numpad separately from the keyboard is easier than finding a place for a full-sized "board". Another option for using the Numpad is to connect to a cash register, terminal, etc. to work as a calculator keyboard or in a similar capacity.

— Keypad. A specialized device in the form of a small (approximately 15 – 20 keys) keyboard under one hand; usually, it is complemented by an arm rest, and often also by side buttons for the thumb. Such devices are especially convenient for games and are mainly used in them — certain game actions can be attached to the keypad buttons (including those that are usually implemented through the menu or a key combination on a standard keyboard). The keypad can both complement the main keyboard and serve as a completely separate game pad.

— Non-standard. Non-standard format keyboards that do not belong to any of the varieties described above. The specific design and use of such devices may vary. So, these can be game models in the form of the left half of a standard keyboard (this part is mainly used in games); ultra-compact models for tablets (see "In the direction"); keyboards for TVs, supplemented with special buttons and designed to be held in two hands in the manner of a gamepad, etc.

— 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 presence on the keyboard of the Fn key(short for function). It belongs to modifiers, similar to Shift or Ctrl: by itself it does not perform any action, but when pressed simultaneously with another key, it changes its original purpose. Fn is often found in compact keyboards (see "Format"), but can also be set in full-sized ones. The features it provides include quickly changing the screen brightness or sound volume directly from the keyboard, using the centre keys as a Numpad, launching individual applications, and so on. Specific features of using the Fn key depend on the keyboard model.

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 presence of an additional palm rest in the design of the keyboard. Such a stand is located in the lower (closest to the user) part of the device and is a kind of continuation of the “board”, providing additional support and increasing the comfort of use. However, comfort is largely a matter of personal preference, and not all users like stands; therefore, most often they are made removable.

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.

Protecting the keyboard from spilling liquid on it. Most waterproof keyboards do not have a full-fledged sealed case and are designed to remain operational in the event of accidental contact with a relatively small amount of liquid (up to 200 mL) — for example, in the classic case of spilling coffee on the keyboard.