What is a keyboard in a computer?

A computer keyboard is an input device that is similar to a typewriter keyboard[1] [2] in that it uses a layout of buttons or keys to function as mechanical levers or electronic switches . Since the 1970s , interaction with computers has primarily been done using keyboards modeled after teleprinters, with the computer mouse joining them in the 1980s. Earlier punched cards and papertape technology have been replaced.

A set of characters are typically engraved or printed on keyboard keys (buttons), and each key press typically corresponds to a single written symbol. But in order to create certain symbols, you might need to press and hold a number of keys at once or sequentially. [3] While most keys generate characters (letters, numbers, or symbols), some keys, like the escape key, can cause the computer to run system commands. In a contemporary computer, key presses are typically interpreted by software; the scan code information sent to the computer only tells it which physical key (or keys) were depressed or depressed. [4].

The keyboard serves as a text entry interface in everyday life, allowing users to enter text, numbers, and symbols into programs like word processors, web browsers, and social media apps. History.

While typewriters are the definitive ancestor of all key-based text entry devices, the computer keyboard as a device for electromechanicaldata entry and communication derives largely from the utility of two devices: teleprinters (or teletypes) and keypunches It was through such devices that modern computer keyboards inherited their layouts

In the 1870s, teleprinter-like machines were used to simultaneously type and transmit stock market text data from the keyboard across telegraph lines to stock ticker machines so that it could be immediately copied and displayed onto tickertape. [5] American mechanical engineers Charles Krum and his son Howard created the teleprinter in its more modern form between 1907 and 1910. Frank Pearne, an electrical engineer, made some early contributions. In the past, individuals like Royal Earl House and Frederick G. developed earlier models independently. Creed

The first keypunch devices were created by Herman Hollerith earlier, and by the 1930s, they had developed to include keys for text and number entry similar to those on standard typewriters. [6].

For the majority of the 20th century, point-to-point and point-to-multipoint communication was primarily handled by the keyboard on the teleprinter, while data entry and storage were primarily handled by the keyboard on the keypunch device for an equal amount of time. The development of the first computers included electric typewriter keyboards. The ENIAC computer used a keypunch device as both the input and paper-based output device, and the BINAC computer also used an electromechanically controlled typewriter for both data entry onto magnetic tape (instead of paper) and data output. [7]

The keyboard remained the primary, most integrated computer peripheral well into the era of personal computing until the introduction of the mouse as a consumer device in 1984 By this point, comparatively graphically-rich icons on the screen had replaced text-only user interfaces with sparse graphics. Despite the fact that mobile personal computing devices like smartphones and tablets have adopted the keyboard as an optional virtual, touchscreen-based method of data entry, keyboards continue to be essential to human-computer interaction today [8]. Types and standards

a Lenovo-made desktop wired keyboard for use on computers.

Differenttypes of keyboards are available and each is designed with a focus on specific features that suit particular needs.[9] Today, most full-size keyboards use one of three different mechanical layouts, usually referred to as simply ISO (ISO/IEC 9995-2), ANSI (ANSI-INCITS 154-1988), and JIS (JIS X 6002-1980), referring roughly to the organizations issuing the relevant worldwide, United States, and Japanese standards, respectively. (In fact, the mechanical layouts referred such as”ISO” and “ANSI” comply to the primary recommendations in the named standards, while each of these standards in fact also allows the other way.) ANSI standard alphanumeric keyboards have keys that are on three-quarter inch centers (0.75 inches (19 mm)), and have a key travel of at least 0.15 inches (3.8 mm).[citation needed]

Modern keyboard models contain a set number of total keys according to their given standard, described as 101, 104, 105, etc. and sold as “Full-size”keyboards.[10] Modern keyboards matching US conventions typically have 104 keys while the 105 key layout is the norm in the rest of the world. This number is not always followed, and individual keys or whole sections are commonly skipped for the sake of compactness or user preference. The most common choice is to not include the numpad, which can usually be fully replaced by thealphanumeric section. Laptops and wireless peripherals often lack duplicate keys and ones seldom used. Function- and arrow keys are nearly always present.

The size and spacing of the keys also affect how big a keyboard is. The practical requirement that the keys must be big enough for fingers to easily press limits the reduction. Alternately, a device is used to press tiny keys. Full-size or desktop.

Desktop computer keyboards come equipped with alphabetic and numeric keys, typographic symbols, punctuation marks, one or more currency symbols, diacritical marks, and a variety of function keys. The variety of glyphs inscribed on a keyboard corresponds to regional customs and linguistic requirements. Electric typewriter keyboards are similar to computer keyboards, but computer keyboards have extra keys like the command key or Windows keys. Laptop-size.

Laptop keyboards typically have fewer keys and a shorter key travel distance.

Keyboards onlaptops and notebook computers usually have a shorter travel distance for the keystroke, shorter over travel distance, and a reduced set of keys The function keys may not be located in the same places as they would be on a typical, full-sized keyboard, and they may not have a numeric keypad. In contrast to the current trend for full-size keyboards, a laptop’s switch mechanism is more likely to be a scissor switch than a rubber dome. modular keyboards.

Flexible keyboards are a fusion of traditional and laptop keyboards, with traditional keyboards having a full key layout and laptop keyboards having short key distances. Additionally, the flexibility enables the user to fold or roll the keyboard for improved storage and transportation. On a hard surface, though, is required for typing on a keyboard. The majority[11] of flexible keyboards available are made of silicone, which renders them resistant to dust and water. This is helpful in hospitals[12] and other filthy or need-to-be-clean settings where keyboards are frequently washed. Handheld.

a mobile AlphaGrip keyboard.

Rather than being laid out flat on top of a table surface, handheld ergonomic keyboards[13][14] are made to be held like a game controller.

Most handheld keyboards have all the alphanumeric and symbol keys of a standard keyboard, but they can only be accessed by simultaneously pressing two sets of keys, one of which serves as a function key, like the “Shift” key on a standard keyboard, to enable capital letters. [15] Portable keyboards give users the freedom to move around a space or lean back in a chair while still being able to type in front of or away from a computer. [16] Some handheld ergonomic keyboard variations also come with a trackball mouse, allowing users to type and move the mouse on one portable device. [17] Thumb-sized.

Smaller external keyboards have been developed for gadgets like PDAs and smartphones that lack a built-in keyboard. In situations with a constrained workspace, small keyboards are also helpful. [18].

Some PDAs, including the Palm Treo, BlackBerry, and some Ultra-Mobile PCs, including the OQO, use a thumb keyboard (thumb board).

Numeric keyboards only have numbers, the addition, subtraction, multiplication, and division mathematical symbols, the decimal point, and a few function keys. They are frequently used to make data entry easier when using smaller keyboards without a numeric keypad, which are typically found on laptop computers. [19] These keys are collectively referred to as a numeric pad, numeric keys, or a numeric keypad, and they can include the following key types: arithmetic operators, numbers, arrow keys, navigation keys, num lock, and the enter key. Multifunctional.

a multipurpose keyboard with LCD function keys.

Beyond the standard keyboard, multifunctional keyboards have additional features. Many are computer keyboards that can be programmed and customized, and some of them can control multiple workstations, PCs, and other information sources, typically in multi-screen work environments. Users have access to additional key features in addition to the standard ones, and they typically only need a single keyboard and mouse to access a variety of sources.

Touch-screen keyboard with multiple functions.

Multipurpose keyboards might have customized keypads, fully programmable function or soft keys for macros/pre-sets, biometric or smart card readers, trackballs, etc. Modern multipurpose keyboards come with touchscreen displays that can be used to stream videos, manage audio and visual media, set alarms, enter data into applications, and more. Users may be able to share access to PCs and other information sources with the help of multifunctional keyboards. a variety of interfaces, including Ethernet, USB, audio, and serial ) are applied to incorporate extraneous gadgets. Video walls can also be easily and directly controlled using some multifunctional keyboards.

Complex, high-performance workplaces for financial traders and control room operators (emergency services, security, air traffic management, industry, utilities management, etc.) are typical environments for multifunctional keyboards. ). layouts that aren’t typical and special-use types Chorded.

Chorded keyboards link actions to groups of keypresses rather than assigning one action to each key as is the case with other keyboards. Due to the large number of possible combinations, chorded keyboards can actually perform more actions on a board using fewer keys. The chorded keyboards on court reporters’ stenotype machines allow them to enter text much more quickly by typing a syllable with each stroke rather than one letter at a time. The majority of court reporters and closed-caption reporters use stenographs, a type of chorded keyboard, which allows for the fastest typists (as of 2007). Some chorded keyboards are also designed to be used in situations where fewer keys are preferred, such as on devices that can only be operated with one hand and on compact mobile devices that lack space for larger keyboards. Because it typically requires practice and memorization of the key combinations to become proficient, chorded keyboards are frequently less desirable. Software

Software keyboards, also known as on-screen keyboards, are frequently just computer programs that show a keyboard image on the screen. Each virtual key can be controlled by a mouse or touchscreen, among other input devices. Due to the additional cost and space requirements of other types of hardware keyboards, software keyboards have become very common in touchscreen-enabled cell phones. On-screen keyboards that can be operated with the mouse are a feature of Microsoft Windows, Mac OS X, and some variations of Linux. When using a software keyboard, the mouse must be moved over the on-screen letters that the program provides. The software writes the appropriate letter in the appropriate place upon clicking a letter. Projection.

Projectionkeyboards project an image of keys, usually with a laser, onto a flat surface. The device then uses a camera or infrared sensor to “watch” where the user’s fingers move, and will count a key as being pressed when it “sees” the user’s finger touch the projected image. Projection keyboards can simulate a full size keyboard from a very small projector. Because the “keys” are simply projected images, they cannot be felt when pressed. Users of projected keyboards often experience increaseddiscomfort in their fingertips because of the lack of “give” when typing. A flat, non-reflective surface is also required for the keys to be projected. Most projection keyboards are made for use with PDAs and smartphones due to their small form factor. Optical keyboard technology

additionally referred to as a photo-optical keyboard, light responsive keyboard, photo-electric keyboard, and optical key actuation detection technology.

LEDs and photo sensors are used in an optical keyboard technology[20] to detect actuated keys optically. The emitters and sensors are typically mounted on a small PCB and placed around the perimeter. The interior of the keyboard is lit from side to side, and the only way to block it are the actuated keys. To determine which key was actuated, the majority of optical keyboards[21] need at least two beams—typically a vertical and a horizontal beam. Some optical keyboards employ a unique key structure that only allows one beam of light per row of keys (typically a horizontal beam) by blocking light in a specific pattern. Alphanumeric key types

To enter each symbol into a word processing program, text editor, data spreadsheet, or other program, the alphabetic, numeric, and punctuation keys are used in the same way as a typewriter keyboard. Many of these keys will generate various symbols when modifier or shift keys are pressed. When the shift key or Caps Lock key is pressed, the alphabetic characters change to uppercase. When the shift key is pressed, the numeric characters are transformed into symbols or punctuation. When certain modifier keys are pressed at the same time as the alphabetic, numeric, and punctuation keys, additional functions may be available. The Space bar is a horizontal bar in the bottom row that is much wider than the other keys. It derives from the mechanical typewriter, just like the alphanumeric characters do. Its primary function during typing is to enter the spaces between words. It is big enough for either hand’s thumb to use without difficulty. The space bar may have features like resizing or closing the current window, half-spacing, or backspacing depending on the operating system when it is used with a modifier key like the control key. The key can be used for a variety of things in addition to typing, such as jumping and marking checkboxes, in computer games and other programs. The space bar is used for pausing and restarting playback in some digital video playback programs. Modifier keys.

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Modifier keys are special keys that modify the normal action of another key, when the two are pressed in combination. For example, Alt+F4 in Microsoft Windows will close the program in an activewindow. In contrast, pressing just F4 will probably do nothing, unless assigned a specific function in a particular program. By themselves, modifier keys usually do nothing. The most widely used modifier keys include the Control key, Shift key and theAlt key. The AltGr key is used to access additional symbols for keys that have three symbols printed on them. On the Macintosh and Apple keyboards, the modifier keys are the Option key andCommand key, respectively. On Sun Microsystems and Lisp machine keyboards, the Meta key is used as a modifier and for Windowskeyboards, there is a Windows key. Compact keyboard layouts often use a Fn key. “Dead keys” allow placement of a diacritic mark, such as an accent, onthe following letter (e.g., the Compose key). The Enter/Return key typically causes a command line, window form or dialog box to operate its default function, which is typically to finish an “entry” and begin the desired process. In word processing applications, pressing the enter key ends a paragraph and starts a new one. Cursor keys

Navigation keys or cursorkeys include a variety of keys which move the cursor to different positions on the screen.[22] Arrow keys are programmed to move the cursor in a specified direction; page scroll keys, such as the Page Up and Page Down keys, scroll the page up and down. The Home key is used to return the cursor to the beginning of the line where the cursor is located; the End key puts the cursor at the end of the line. The Tabkey advances the cursor to the next tab stop. The Insert key is mainly used to switch between overtype mode, in which the cursor overwrites any text that is present on and after its current location, and insert mode, where the cursor inserts a character at its current position, forcing all characters past it one position further. TheDelete key discards the character ahead of the cursor’s position, moving all following characters one position “back” towards the freed place. On many notebook computer keyboards the key labeled Delete (sometimes Delete and Backspace are printed on the same key) serves the same purpose as a Backspace key. The Backspacekey deletes the preceding character. Lock keys lock part of a keyboard, depending on the settings selected. The lock keys are scattered around the keyboard. Most styles of keyboards have three LEDs indicating which locks are enabled, in the upper right corner above the numeric pad. The lock keys include Scroll lock, Num lock (which allows the use of the numeric keypad), and Caps lock.[23]

System commands

Keyboard for a dumb terminal and mainframe model 4800-52, c. mid-1980s. The arrow and modifier keys, line feed, break, blank, and repeat keys have an odd configuration.

The SysRq and Print screen commands often sharethe same key. SysRq was used in earlier computers as a “panic” button to recover from crashes (and it is still used in this sense to some extent by the Linux kernel; see Magic SysRq key). The Print screen command used to capture the entire screen and send it to the printer, but in the present it usuallyputs a screenshot in the clipboard. Break key

There is no longer a clear purpose for the Break/Pause key. Its inception can be traced back to teleprinter users who desired a key that would momentarily cut off the communications line. The Break key can be employed by software in a variety of ways, including to switch between multiple login sessions, to end a program, or to break a modem connection. Break is used in programming, especially in old DOS-style BASIC, Pascal, and C, along with Ctrl, to halt the execution of a program. Furthermore, this combination behaves exactly like Ctrl C in Linux and its variants, as well as in many DOS programs. On modern keyboards, the break key is usually labeled Pause/Break The Windows key and Pause brings up the system properties in most Windows environments. Escape key.

The escape key (esc) has a variety of meanings according to Operating System, application or both. “Nearly all of the time”,[24] it signalsStop,[25] QUIT,[26] or “let me get out of a dialog” (or pop-upwindow).[24][27] It triggers the Stop function in many web browsers.[28]

The escape key was a standard part of the keyboard for the 1964-released Teletype Model 33, which was used with many early minicomputers. [29] The DECVT50, released in July 1974, also included an Esc key. The Esc key is widely used in text editors like TECO (circa 1963) and Emacs (circa 1985).

The term “escape sequence” refers to a group of characters that are typically preceded by the escape character. Historically, it also served as a type of shift key, causing one or more subsequent characters to be interpreted differently. [30][31].

On machines running Microsoft Windows, prior to the implementation of the Windows key on keyboards, the typical practice for invoking the “start” button was to hold down the control key and press escape. This process still works inWindows 95, 98, Me, NT 4, 2000, XP, Vista, 7, 8, and 10.[32] Enter key or Return key

The “enter key” Enter and the “return key” Return are two keys that are similar to one another but have different and overlapping functions that depend on the operating system and application. There are two such keys on full-size keyboards; one is located in the alphanumeric keys and the other is located in the numeric keys. The enter key’s function is to verify what has been typed. The return key is based on the original line feed/carriage return function of typewriters: in many word processors, for instance, the return key ends a paragraph; in a spreadsheet, it completes the current cell and moves to the next cell.

In contrast to ANSI keyboards, which have an inverse L-shaped shape and place the Enter key in a single row (typically the third from the bottom), ISO keyboards have the Enter key spread across two rows. shift key

The Shift key’s function is to activate the first alternate key’s functionality while it is pressed simultaneously with another key. Shift letter provides the upper case version of that letter for alphabetic keys. Other keys have symbols engraved on them that represent both the shifted and unshifted results. When combined with other control keys (like Ctrl, Alt, or AltGr), the outcome depends on the system and application.

On keyboards designed for Windows-based computers, you’ll find the Menu or Application key. Instead of using the standard right mouse button to open a context menu, it is used the keyboard. A cursor hovering over a menu is typically used as the key’s icon. The icon’s cursor may not be visible on all Samsung keyboards, which only display the menu. The Windows key and this key were both created at the same time. When the right mouse button is missing from the mouse, this key is typically used. To prevent users from right-clicking, some Windows public terminals don’t have a Menu key on their keyboard (however, in many Windows applications, a similar functionality can be accessed with the Shift F10 keyboard shortcut). Numbering pad.

To the right of the alphabetic keyboard on most, but not all, computer keyboards is a numeric keypad that contains numbers, basic mathematical symbols (e.g. g. for example, addition and subtraction. ), a couple of function keys, and. Most desktop keyboards have an accounting pad or number pad on the right side of the keyboard, in addition to the row of number keys above the top alphabetic row. If num lock is enabled, the numbers on these keys duplicate the number row; otherwise, they serve the engraved functions. This pad also includes command symbols for calculations like addition, subtraction, multiplication, and division. The equal sign is indicated by the enter key in these keys. Miscellaneous

Some keyboards have multimedia buttons that enable quick access to the Internet or speaker volume.

Language input keys may be present on Japanese/Korean keyboards, allowing users to switch between different languages. Some keyboards have powermanagement keys (e g , power key, sleep key, and wake key); Internet keys to access a web browser or email; multimedia keys, such as volume controls; or keys that can be programmed by the user to launch a specific application or a command like minimizing all windows. different layouts

A variety of keyboard layouts can be installed on an operating system, and users can switch between them using either built-in OS features or third-party applications. Support for adding keyboard layouts and selecting them is offered by Microsoft Windows[33], Linux[34], and Mac[35]. Illumination.

When designing equipment for mobile use, keyboards and keypads may be internally illuminated. Backlighting is a feature that can be used on both internal and external keyboards. Backlit external keyboards can connect via wired USB or wirelessly and run on batteries. In low-light situations, illumination makes it easier to use the keyboard or keypad.

Only the keys may be uniformly backlit for overall productivity, with no distracting light surrounding the keys.

keys with built-in LED signal lights.

With multiple colors and color-coded keys to make it simpler for gamers to locate command keys while playing in a dark room, many gaming keyboards are made to have both an aesthetic and functional appeal. [36] Many keyboards that aren’t otherwise illuminated may have tiny LED indicator lights in a few crucial function keys or elsewhere on the housing, depending on whether or not their function is activated (see photo). Switches with a key.

The key switches in the first electronic keyboards from the early 1970s were individual switches inserted into holes in metal frames. These keyboards were used in mainframe data terminals and ranged in price from 80 to 120 USD. Reed switches, which use contacts affected by a magnet mounted on the switchplunger and enclosed in a vacuum in a glass capsule, were the most widely used switch types. [Citation needed].

Direct-contact key switches that were less expensive and had a ten million cycle rating were introduced in the middle of the 1970s, but because they were exposed to the environment, their lifespan was significantly shorter. However, this was later accepted for use in computer terminals, which at the time started to have shorter model lifespans as technology advanced. [37].

In 1978, Key Tronic Corporation introduced keyboards with capacitive-based switches, one of the first keyboard technologies not to use self-containedswitches.[38] There was simply a sponge pad with a conductive-coated Mylar plastic sheet on the switch plunger, and two half-moon trace patterns on the printed circuit board below. As the key was depressed, the capacitance between the plunger pad and the patterns on the PCB below changed, which was detected by integrated circuits (IC). These keyboards were claimed to have thesame reliability as the other “solid-state switch” keyboards such as inductive and Hall-effect, but competitive with direct-contact keyboards. Prices of $60 for keyboards were achieved, and Key Tronic rapidly became the largest independent keyboard manufacturer.

Meanwhile, IBM made their own keyboards, using their own patented technology: Keys on older IBMkeyboards[39] were made with a “buckling spring” mechanism, in which a coil spring under the key buckles under pressure from the user’s finger, triggering a hammer that presses two plastic sheets (membranes) with conductive traces together, completing a circuit.This produces a clicking sound and gives physical feedback for the typist, indicating that the key has been depressed.[40]

Key travel distance on the earliest electronic keyboards was 0 for typewriters. A 187-inch (4. Keytops were half-inches (12 (75mm) in diameter. Keyboards were about two inches (5 cm) thick and 0.27 inches (7mm) high. Less key travel was eventually accepted by consumers and reached zero over time. 110 inches (2. 79mm) Coincidentally, Key Tronic was the first business to release a keyboard that was only a little over an inch thick. The thickness of modern keyboards is only about half an inch.

Keyboard with some keytops removed to show theCherry MX “Black” switches it is based on. MX switches are a common choice for mechanical keyboards.

The tactile, non-clicky “brown” version of the Cherry MX switch shown in disassembled form (four parts,left and centre), with the top off (top right) and reassembled (bottom right).

Keytops are an important element of keyboards. In the beginning, keyboard keytops had a “dish shape” on top, like typewriters before them. Keyboard key legends must be extremely durable over tens of millions of depressions, since they are subjected to extreme mechanical wear from fingers and fingernails, and subject to hand oils and creams, so engraving and filling key legends with paint, as was donepreviously for individual switches, was never acceptable. So, for the first electronic keyboards, the key legends were produced by two-shot (or double-shot, or two-color) molding, where either the key shell or the inside of the key with the key legend was molded first, and then the other color molded second. But, to save cost, other methods were explored, such assublimation printing and laser engraving, both methods which could be used to print a whole keyboard at the same time.

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Initially, sublimation printing, where a special ink is printed onto the keycap surface and the application of heat causes the ink molecules to penetrate andcommingle with the plastic modules, had a problem because finger oils caused the molecules to disperse, but then a necessarily very hard clear coating was applied to prevent this. Coincident with sublimation printing, which was first used in high volume by IBM on their keyboards, was the introduction by IBM of single-curved-dish keycaps to facilitate quality printing of key legends by having a consistently curved surface instead of a dish. But one problem with sublimation or laser printing wasthat the processes took too long and only dark legends could be printed on light-colored keys. On another note, IBM was unique in using separate shells, or “keycaps”, on keytop bases. This might have made their manufacturing of different keyboard layouts more flexible, but the reason for doing this was that the plastic material that needed to be used for sublimation printing was different from standard ABS keytopplastic material.

Three final mechanical technologies brought keyboards to where they are today, driving the cost well under $10: “Monoblock” keyboard designs were developed where individual switch housings were eliminated and a one-piece “monoblock” housing used instead. This was possible because of molding techniques that could provide very tight tolerances for the switch-plunger holes and guides across the width of the keyboard so that the key plunger-to-housing clearanceswere not too tight or too loose, either of which could cause the keys to bind. The use of contact-switch membrane sheets under the monoblock. This technology came from flat-panel switch membranes, where the switch contacts are printed inside of a top and bottom layer, with a spacer layer in between, so that when pressure is applied to the area above, a direct electrical contact is made.The membrane layers can be printed by very-high volume, low-cost “reel-to-reel” printing machines, with each keyboard membrane cut and punched out afterwards.

Plastic materials played a very important part in the development and progress of electronic keyboards. Until “monoblocks” came along, GE’s “self-lubricating” Delrin was the only plastic material for keyboardswitch plungers that could withstand the beating over tens of millions of cycles of lifetime use. Greasing or oiling switch plungers was undesirable because it would attract dirt over time which would eventually affect the feel and even bind the key switches (although keyboard manufacturers would sometimes sneak this into their keyboards, especially if they could not control the tolerances of the key plungers andhousings well enough to have a smooth key depression feel or prevent binding). But Delrin was only available in black and white, and was not suitable for keytops (too soft), so keytops use ABS plastic. However, as plastic molding advanced in maintaining tight tolerances, and as key travel length reduced from 0.187-inch to 0.110-inch (4.75 mm to 2.79 mm),single-part keytop/plungers could be made of ABS, with the keyboard monoblocks also made of ABS.

In common use, the term “mechanical keyboard” refers to a keyboard with individual mechanical key switches, each of which contains a fully encased plunger with a spring below it and metallic electrical contacts on a side. The plunger sits on the spring and the key will often close the contacts when the plunger is pressed half-way. Other switches require the plunger to be fully pressed down.The depth at which the plunger must be pressed for the contacts to close is known as the activation distance. Analog keyboards with key switches whose activation distance can be reconfigured through software, optical switches that work by blocking laser beams, and Hall Effect keyboards that use key switches that use a magnet to activate a hall sensor, are also available. Control processor

Key presses on computer keyboards are translated into keycodes (typically scancodes) by control circuitry so that the electronics of the computer can understand them. The printed circuit board connects the key switches in an electrical X-Y matrix, where a voltage is sequentially applied to the Y lines and a key press is sequentially detected by scanning the Xlines.

Discrete electronic components were used in the first computer keyboards, which were made for mainframe computer data terminals. Despite the fact that General Instruments released the first keyboard microprocessor in 1972, keyboards have been using the single-chip 8048 microcontroller variant since 1978. [42] The keyboard switch matrix is wired to its inputs, it converts the keystrokes to key codes, and, for a detached keyboard, sends the codes down a serial cable (the keyboard cord) to the main processor on the computer motherboard Insofar as the computer’s electronics regulate the illumination of the caps lock, num lock, and scroll lock lights, this serial keyboard cable communication is only bi-directional in that regard.

Pressing the caps lock key can help you determine whether the computer has crashed. In order to turn on the light, the main computer must be operational when the keyboard driver receives the key code from the keyboard and is running. All the other indicator lights work in a similar way The Shift, Alt, and Control states of the keyboard are also tracked by the keyboard driver.

Some lower-quality keyboards have multiple or false key entries due to inadequate electrical designs. These are caused by inadequate keyswitch “debouncing” or inadequate keyswitch matrix layout that don’t allow multiple keys to be depressed at the same time, both circumstances which are explained below:

When pressing a keyboard key, the key contacts may “bounce” against each other for several milliseconds before they settle into firm contact. When released, theybounce some more until they revert to the uncontacted state. If the computer were watching for each pulse, it would see many keystrokes for what the user thought was just one. To resolve this problem, the processor in a keyboard (or computer) “debounces” the keystrokes, by aggregating them across time to produce one “confirmed” keystroke.

Some low-quality keyboards also suffer problems withrollover (that is, when multiple keys pressed at the same time, or when keys are pressed so fast that multiple keys are down within the same milliseconds). Early “solid-state” keyswitch keyboards did not have this problem because the keyswitches are electrically isolated from each other, and early “direct-contact” keyswitch keyboards avoided this problem by having isolation diodes for everykeyswitch. These early keyboards had “n-key” rollover, which means any number of keys can be depressed and the keyboard will still recognize the next key depressed. But when three keys are pressed (electrically closed) at the same time in a “direct contact” keyswitch matrix that doesn’t have isolation diodes, the keyboard electronics can see a fourth “phantom” key which is the intersection of the X and Y lines of the three keys. Some types of keyboard circuitry will register a maximum number ofkeys at one time. “Three-key” rollover, also called “phantom key blocking” or “phantom key lockout”, will only register three keys and ignore all others until one of the three keys is lifted. This is undesirable, especially for fast typing (hitting new keys before the fingers can release previous keys), and games (designed for multiple key presses).

As direct-contact membrane keyboards gained popularity, the available rollover of keys was optimized by analyzing the most popular key sequences and placing these keys so that they do not potentially produce phantom keys in the electrical key matrix (for example, simply placing three or four keys that might be depressed simultaneously on the same X or same Y line, so that a phantom key intersection/short cannot happen). As a result, blocking a third key is typically not an issue. But poorer keyboard designs and ignorant engineers might not be aware of these tricks, and it can still be a problem in games because different games have drastically different or configurable layouts. Relationship types.

There are a number of ways to attach a keyboard to a system unit (or more specifically, to its keyboard controller) using cables, including the standard AT connector frequently found on motherboards, which was eventually replaced by the PS/2 and the USB connection. The keyboard connector on Apple’s previous generation of computers was the exclusive Apple Desktop Bus.

Wireless keyboards have gained popularity. A wireless keyboard must have an integrated transmitter and a receiver that are both connected to the keyboard port on the computer. Wireless keyboards can communicate using either radio frequency (RF) or infrared (IR) signals. The receiver of a wireless keyboard may be integrated into a computer if it uses the widely used Bluetooth radio communication protocol. Wireless keyboards may be vulnerable to data eavesdropping and require batteries for power. With the help of small solar panels and either natural or artificial light, wireless solar keyboards recharge their batteries. An early IR keyboard can be seen in the 1984 Apricot Portable. different techniques for entering text.

Users with limited mobility can use the on-screen keyboard controlled by the mouse.

For converting existing text that has already been written down but is not in a machine-readable format (for instance, a book from the 1940s composed in Linotype), optical character recognition (OCR) is preferred to rekeying. In other words, a person could retype the text from an image into editabletext (i.e., a string of character codes), or a computer could analyze the image and determine what each character represents. Google Book Search is just one example of how OCR technology has already advanced to an impressive level and holds great promise for the future.

Speech recognition turns spoken words into text that can be read by computers, or a series of character codes. This technology has also developed to a sophisticated level and is used in many different types of software. For some applications (e. g Speech recognition is beginning to take the place of the keyboard in various tasks (such as transcription of legal or medical dictation; journalism; writing essays or novels). However, the lack of privacy when using voice commands and dictation renders this type of input inappropriate for many environments.

In situations where a physical keyboard would be inappropriate or impossible to use, pointing devices can be used to enter text or characters. These accessories typically display characters on a display in a way that makes it easy to find frequently used characters or character combinations. Popular examples of this kind of input are Graffiti, Dasher and on-screen virtual keyboards Keystroke logging is an issue.

Unencrypted wireless Bluetooth keyboards are known to be vulnerable to signal theft, which can be done by hiding a covert listening device in the same room as the keyboard and using it to sniff and record Bluetooth packets to log the keys that the user types. This vulnerability is known to exist in Microsoft wireless keyboards manufactured in 2011 and earlier. [43].

The practice of recording and capturing user keystrokes is known as keystroke logging (also known as keylogging). While it is legitimately used by law enforcement to track down illegal activity or by businesses to measure employee productivity on specific clerical tasks, hackers also use it for a variety of nefarious or malicious purposes. Keyloggers are tools that hackers use to obtain encryption keys or passwords and get around other security measures.

Both hardware and software tools are available to obtain keystroke logging. Hardware key loggers can be found inside common keyboards or attached to the keyboard cable. Software keyloggers operate on the operating system of the target computer and gain unauthorized access to the hardware, connect to the keyboard using features offered by the OS, or use remote access software to send recorded data from the target computer to a remote location. Some hackers also use wireless keylogger sniffers to collect packets of data beingtransferred from a wireless keyboard and its receiver, and then they crack the encryption key being used to secure wireless communications between the two devices

Anti-spyware applications are able to detect many keyloggers and cleanse them. Responsible vendors of monitoring software support detection by anti-spyware programs, thus preventing abuse of the software. Enabling afirewall does not stop keyloggers per se, but can possibly prevent transmission of the logged material over the net if properly configured. Network monitors (also known as reverse-firewalls) can be used to alert the user whenever an application attempts to make a network connection.This gives the user the chance to prevent the keylogger from “phoning home” with his or her typed information. Automatic form-filling programs can prevent keylogging entirely by not using the keyboard at all. Most keyloggers can be fooled by alternating between typing the login credentials and typing characters somewhere else in the focuswindow.[44]

Keyboards are also known to emit electromagnetic signatures that can be detected using special spying equipment to reconstruct the keys pressed on the keyboard. Neal O’Farrell, executive director of the Identity Theft Council, revealed to InformationWeek that “More than 25 years ago, a couple of former spooks showed me how they could capture a user’s ATM PIN,from a van parked across the street, simply by capturing and decoding the electromagnetic signals generated by every keystroke,” O’Farrell said. “They could even capture keystrokes from computers in nearby offices, but the technology wasn’t sophisticated enough to focus in on any specific computer.”[45] Physical injury

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To avoid repetitive strain injuries, which can develop over time and result in long-term disability, proper ergonomic design of computer keyboard desks is required. Research indicates that a 45-degree reclined position is healthier and that the upright position, which was previously recommended, can cause degenerative disc disease. [47].

Any keyboard use has the potential to seriously harm the hands, wrists, arms, neck, or back (through carpal tunnel syndrome or other forms of repetitive strain injury). [48] By taking frequent, brief breaks to get up and move around a few times every hour, the risks of injuries can be decreased. Additionally, users should switch up their tasks throughout the day to prevent overusing their hands and wrists. A person should type at the keyboard with relaxed shoulders and elbows out to the sides. The keyboard and mouse should be placed so that reaching is not necessary. The keyboard tray and chair height should be adjusted to ensure that the wrists are straight, and the wrists shouldn’t rest on the edge of a sharp table. [49] When typing, wrist or palm rests shouldn’t be used. [50]

Some adaptive technology, such as special keyboards, mouse substitutes, pen tablet interfaces, and speech recognition software, can lower the risk of injury. Software designed to help people pause is called Pause. The solution might be to switch to a mouse that is much more ergonomic, like a vertical mouse or joystick mouse.

By using a touchpad or a stylus pen with a graphic tablet, in place of a mouse, one can lessen the repetitive strain on the arms and hands.[51]

See also

  • Digital pen
  • Dvorak
  • IBM PC keyboard
  • Keyboard protector
  • Maltron
  • Overlay keyboard
  • Table of keyboard shortcuts


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  • External links

    • How Computer Keyboards Work atHowStuffWorks
    • “Art of Assembly Language: Chapter Twenty”: The PC Keyboard
    • Keyboard matrix circuits
    • PC World. “The 10 worst PC Keyboards of All Time”.

    Esc, F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12 PrtScn/SysRq ScrollLock, Pause/Break, Insert Home, PgUp, NumLock, Delete End, PgDn, 7 8-9, 4–6, 1–2, 3, Enter 0 Ins are the keys on an IBM PC keyboard with Windows. Del

    What is a keyboard in a computer? : The ability to enter text into a computer or other electronic device is made possible by the use of a keyboard, a peripheral device. The simplest way for a user to interact with a computer is through a keyboard, which is an input device.

    What is keyboard and its type?

    It is made up of numerous buttons that can be used to create letters, numbers, and symbols as well as unique keys like the Windows and Alt keys that can also be used for other purposes. The keyboard’s layout, which was inspired by typewriter keyboards, has numbers and letters arranged in a way that makes it easier to type quickly.

    What is keyboard with example?

    The definition of a keyboard is a row of keys on a piano, computer, typewriter, etc. An example of keyboard is where the arrangement of keys “QWERTY” is found.

    What are the 3 types of keyboards?

    The various keyboard technologies enable a range of user experiences, including how firmly a key must be depressed to type a character. QWERTY keyboards Wire-based keyboards. Number Keypads. A comfortable keyboard. a wireless keyboard. USB keyboards. Bluetooth keyboards enchanted keyboards.

    Additional Question — What is a keyboard in a computer?

    What are uses of keyboard?

    Letters, words, and numbers can all be entered into a computer using a keyboard. When you type, you press each key on the keyboard separately. The number keys on the keyboard’s top row can also be found there, to the right.

    What are the parts of keyboard?

    The following list of the keyboard’s five components includes each part. Breakaway Key. Tab Key. Keyboard shortcut for Alt. Clt Key. Space Bar Key.

    What are the 3 types of mouse?

    The 11 Types of Computer Mice. Wireless Mouse. Bluetooth Mouse Mouse with Bluetooth. contrasting Wired with versus wireless a Bluetooth mouse. Monitor Mouse. Laser Mouse contrasting Trackball and optical versus a laser mouse. Magic Mouse

    What are the major keyboard types?

    Depending on the size and number of keys, there are four main types of computer keyboards in use worldwide: QWERTY, AZERTY, DVORAK, and QWERTZ.

    What are the 3 types of mechanical switches?

    There are three main categories of switches: linear, tactile, and clicky. The majority of major corporations label them as brown (tactile), blue (clicky), and red (linear), but it differs for each brand. Each gives off a distinct vibe and produces its own sound feedback.

    How many keyboard are there?

    While the rest of the world typically uses a keyboard layout with 105 keys, modern keyboards that follow US conventions typically have 104 keys. Individual keys or entire sections are frequently skipped for the sake of compactness or user preference, so this number is not always adhered to.

    What are the 7 special keys in keyboard?

    These shortcuts are especially helpful when managing files and text. save with Ctrl-S. Open with Ctrl-O. Type “new” with the keyboard shortcut Ctrl. copy with Ctrl-C. Paste with Ctrl-V. Ctrl-X to cut. Undo is available with the key combination Ctrl-Z. Using Ctrl-A, select all.

    What are the 2 types of keyboard?

    The two main categories of computer keyboards are Basic and Extended. The 104 keys on the Basic keyboard are sufficient to carry out all actions that can be taken on a Windows PC. Additional keys might be present on the Extended keyboard, and each manufacturer has a different design.

    What are the 6 types of keys in keyboard?

    Each key and key type has been designed to serve a certain purpose The alphabet. Since we’re discussing standard keyboards, you can access the letter or alphabet keys from A to Z. Numerical Keys. The numeric keys 0 to 9 are included in the number keys Special Keys or Control Keys The function keys. Navigational Keys

    What are the 10 parts of the keyboard?

    Depending on their purpose, the keys on your keyboard can be categorized into a number of groups: Typing (alphanumeric) keys. The letter, number, punctuation, and symbol keys on these keys are identical to those on a conventional typewriter. Control keys Keyboard shortcuts directional keys. The numeric keypad.

    What are the 12 function keys on a keyboard?

    ContentsThe F1 key The F2 key The F3 key The F4 key The F5 key The F6 key The F7 key The F8 key

    What is function of F1 to F12 keys?

    Special alternate commands are assigned to the FUNCTION keys F1 through F12. The name “enhanced function keys” refers to these keys. You can access frequently used commands quickly with the help of enhanced function keys, which can boost your productivity. Usually, the keys themselves or the print above them will have these commands.

    What is F1 F2 F3 F4 F5 f6 F7 F8 f9 f10?

    The function keys or F-keys on a computer keyboard, labeled F1 through F12, are keys that have a special function defined by the operating system, or by a currently running program They may be combined with the Alt or Ctrl keys

    What is F7 key used for?

    In Microsoft applications like Microsoft Excel, Microsoft Word, Microsoft Outlook, and other Office products, the F7 key is frequently used to spell and grammar check a document. The highlighted word is checked in the Thesaurus by pressing Shift F7.

    What is F5 key used for?

    Nearly all computer keyboards have a function key at the top called the F5 key. In order to refresh a web page in an Internet browser, the key is typically used.

    What is F1 F2 F3 on the keyboard?

    F1 Opens the Help screen for almost every program F2 Allows you to rename a selected file or folder F3 Opens a search feature for an application that is active at the moment F4 Alt + F4 closes the active window

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