To process information using a PC, the user must enter information into the computer. The main data input and system control devices are the keyboard, mouse, joystick. However, such input devices as a scanner, digital camera, digitizer are becoming more widespread.
The keyboard is the main input device in the PC, although the mouse is increasingly taking over the performance of control functions. Keys are the main element of the keyboard. The signal when a key is pressed is registered by the keyboard controller and transmitted in the form of a so-called scan code to the motherboard.
The scan code is a one-byte number, the lower 7 bits of which represent the identification number assigned to each key.
According to the design, the keyboards are divided into keyboards with plastic pins, with a click, with microswitches and touch.
When you press these keys, an alphanumeric character is entered into the computer. Which one depends on whether the mode is set 
entering Latin letters or Russian letters, and whether or not the SHIFT key is pressed.
Note: The name of the SHIFT key means "shift", it is inherited from typewriters, on which to enter uppercase (capital) letters it was necessary to move (usually lift up) the typewriter's typewriter.
The SPACE key, like on a typewriter, the largest key, located under the block of alphanumeric keys, is used to enter a space (empty character).
The CAPS LOCK key is used to lock the caps mode. In this mode, pressing the alphabet keys normally enters uppercase letters, while holding down the SHIFT key enters lowercase letters (this is the opposite of what is done in normal mode). Capital letters mode (often referred to as "CAPS LOCK mode"") is useful when entering text that consists of such letters. Pressing the CAPS LOCK key again cancels the caps mode.
Note: sometimes the CAPS LOCK key is sometimes used for other purposes, such as switching to the Russian alphabet.
On the top of the keyboard there is a block of so-called function keys F1-F12, the order of using these keys is determined by the program and operating system with which we are currently working. In many programs, when you press the F1 key, the built-in help for the program is displayed on the screen. (see other key values below).
The HOME, END, PgUp, PgDn, right, left, up, down keys are called cursor keys. As a rule, clicking on them leads to moving the cursor (indicator of the current place in the document being processed) in the corresponding direction or to "turning" the text displayed on the screen. However, in other situations, these keys (as well as their combinations with the CTRL, ALT, SHIFT keys) may have different meanings.
Comment:
- When processing documents, the cursor is usually represented by a vertical bar, and in DOS programs by a blinking character, similar to an underscore.
- The key names PgUp PgDn mean ""page up"" and ""page down"" . usually pressing these keys will scroll the contents of the screen (say, when editing a document) a page up and down.
- Normally, pressing the HOME END key moves the cursor to the beginning and end of the line.
The key block on the right side of a standard 101-key keyboard serves two purposes. In digit lock mode (mode "" Num Lock'"), this block is convenient for entering numerical information and arithmetic signs. In this mode, when you press the white keys from this block, numbers from 0 to 9 and a period are entered. And if the digit lock mode (Num Lock mode) is turned off, then these keys duplicate the cursor keys, as well as the INSERT DELETE keys.The lock mode is turned on and off by pressing the Num Lock key.
Note: the name ""Num Lock"" is a literal translation 
means "fixing numbers"
In the upper right corner of the 101-key keyboard are indicators for Num Lock mode, Caps Lock mode, and Scroll Lock mode. These indicators light up when the corresponding modes are turned on, and go out when these modes are turned off.
Special keyboard keys
Special (service) keys perform the following main functions:
ENTER - input of commands to be executed by the processor, (on some keyboards Return, Enter, CR) is usually used to end the input of an object. For example, when entering DOS commands, the input of each command (command line) must end with pressing the Enter key. When typing text in the document editor, pressing the Enter key usually ends the entry of a paragraph.
ESC - cancel any action;
TAB - move the cursor to the tabulation position;
INS - switching the character insertion mode at the cursor position to the character backspace mode at the cursor position;
DEL - delete character at cursor position;
BACKSPACE - delete character to the left of the cursor;
HOME - move the cursor to the beginning of the text;
END - move the cursor to the end of the text;
PGUP - moving the cursor one screen page up in the text;
PGDN - moving the cursor down one screen page in the text;
ALT and CTRL - when these keys are pressed simultaneously with any other, a change in the action of the latter is caused;
SHIFT - holding this key down provides a case change;
CAPS LOCK - fixing / unfixing the case of capital letters;
Keyboard types
All keyboards are divided into three types:
- Full (Regular keyboard 101\102, now 104, 108)
- Multimedia (Keyboard with an additional set of keys, such as keys for working on the Internet, keys for sound control, etc.)
- Incomplete (Keyboard on Notebooks)
Working with the price list
When choosing a keyboard, it is necessary to consider some of the characteristics, for example:
- Keyboard. Specifications.
- Describe the components from the price list
- Defender Callisto Compact KM-4610S Silver&Black PS/2 104KL+15KL M/Med
- Genius KB-380 Calculator Ergo Black USB 104CL+14CL M/Med+Calculator
All alphanumeric keys are shown in fig. 29. They are designed to enter textual information and commands. Each key can work in several modes, for example, the A (English) key can be used to enter four characters: a, A, f, F. In the first case (pair a, A), the case is simply changed - lower / upper, in the second (f , Ф) the layout has been changed (Latin/Russian).
Rice. 29. Alphanumeric keys.
To enter an uppercase (large) letter, you need to press the service key Shift and, without releasing it, press the desired letter. If you press a key without Shift, then a lowercase (small) character will be entered, and if you press Shift, an uppercase (large) character will be entered.
Pay attention to the first row of alphanumeric keys:
At the top of each of these keys is a second character:
Shift is used to enter "upper" characters. For example, if you want to enter an exclamation point, then you need to press Shift without releasing this key, press 1 and release both keys.
Some keys have a red symbol at the top along with a black character, for example, above 7 there are two characters, "^" and "?". Red color means that this character can be entered in the Russian layout, i.e. when the keyboard is switched to Russian. When the keyboard is switched to English and you press Shift and 7, the "&" character will be entered. And if the keyboard is switched to Russian and you also press Shift and 7, then the “?” character will be entered. That is why it is recommended that you first buy the cheapest keyboards, those that cost $5. Everything is as it should be on them: white keys of the keyboard, symbols are applied in black English alphabet, and in red - Russian. This makes it easier for a novice user to focus on the characters of the desired alphabet. And when all characters are shown in black (or white - on a fashionable black keyboard), then everything merges and it is difficult to find the right key. Why do you think professional users rarely buy trendy keyboards? Not only because they do not pay attention to all these "bells and whistles". They don't look at the keyboard at all. The question is: what's the point of paying $40 for an input device that you can buy for $5 and you won't even look at it? After a while, you, too, will be able to work with the keyboard blindly. Then it will not matter to you what color these or those symbols are applied - the fingers themselves will stretch where necessary.
We will talk about switching input languages separately. And now consider the input mode of uppercase (large) letters. The keyboard has a special key - CAPS LOCK. It is located between the left Shift key and the Tab key. When you press this key, the CAPS LOCK indicator on the keyboard will light up. After that, ALL ALPHA KEYS WILL WORK IN "CAPITAL" MODE - AS IF YOU ARE CONSTANTLY HOLDING SHIFT. This mode is convenient when you need to enter a relatively large text in capital letters - do not constantly hold Shift. The CAPS LOCK key only affects alphabetic keys, i.e. those used to enter alphabetic characters. CAPS LOCK does not apply to number keys and punctuation character input keys.
The largest key on the keyboard is the Spacebar, where nothing is written or drawn. After all, a space is an empty character, so nothing is shown there.
Introduction to the keyboard.
So, the topmost Esc key in the left corner of the keyboard reads “escape” - it cancels, below the key in the form of a wavy line is called the tilde, it is also the letter Yoyo. Below the tilde is the Tab key.
Going further, the Caps Lock key turns on the capital letters input mode, while the middle light on the right side of the keyboard lights up, the text is entered in capital letters. Shift key, when the Shift key is pressed, the letters are displayed in uppercase, large, but if you type text with the Shift key pressed, the characters are displayed as lowercase, small.
The Shift key is used when entering characters that require capitalization, such as first name, last name, name of something. To do this, press the Shift key to type the first letter, for example, of a name, then release the Shift key, and then type as usual.
Even lower, the Ctrl key - control, to perform any action is used as a key combination, for example, "Ctrl + P" - print. The next key to the right Microsoft flag - opens the main Windows menu - start - in the lower left corner of the screen. The next Alt key is an alternative, also used as a keyboard shortcut.
The long key - space, is designed to separate words from each other with an empty character. Further, the Alt, Ctrl and Shift keys on the right of the keyboard repeat the same functions as the corresponding keys on the left of the keyboard. The key in the form of text with an arrow opens the context menu of the active object or is identical to the right mouse button. The Enter key - means enter or starts the program for execution or moves the cursor to a new line in a text editor.
Above is the Backspace key, it may look like an arrow pointing to the left - it removes the character to the left of the cursor. If earlier it was impossible to correct a mistake made on a typewriter, then on a computer this is done very easily, just click on the Backspace key to remove the character to the left of the cursor, i.e. the mistake made.
Function keys
The top row of the keyboard is F1-F12, with the help of these keys or their combinations you can control the computer. For example, open a help window, an explorer window, turn the computer on and off.
Cursor keys
Insert "insert" - insert. By default, there is an insert mode, for example, if a letter is missing in a word, then you need to mark the place of the missing letter with the cursor and type the corresponding letter, which pushes the parts of the word apart and is inserted between its parts. If you click on the Insert key, then the replace mode is turned on. In this case, the incorrectly typed character is replaced by the correct one.
The Delete key "divides" - deletes the character to the right of the cursor. Clavina Home "home" - means home, quickly moves the cursor to the beginning of the line. Key End "end" - means the end, quickly moves the cursor to the end of the line. Key PgUp "page up" - page up, PgDn "page down" - page down, respectively.
Now let's look at the arrows, here I think everything is clear, the arrows show the direction of the cursor.
Auxiliary numeric keypad
Please note that the number keys are located in the same way as the keys on the calculator. This is done for the convenience of working with numbers, for calculations. There is also an Enter key to confirm the result. The Num Lock key is designed to switch the mode numeric keypad to cursor key mode. By default, the numeric keypad mode is set and the first light is green.
If you press the Num Lock key, the light turns off and the cursor keys mode turns on. Key "+" - addition, "-" - subtraction, "*" - multiplication, "/" (forward slash - slash) - division. There are arrows left, right, down and up; there are Insert, Delete, Home, End, PgUp and PgDn keys.
The Scroll Lock key turns on the mode in which you can copy the contents of the screen, while turning on the third light on the keyboard panel. After switching on this mode you can press the Print Screen key, just it copies what is currently on the monitor screen, in the future you can print a copy.
To pause the computer, the Pause key is used, it may still have the second name Break, until you press some other key.
keyboard shortcuts
Key combinations are performed by pressing one key and, without releasing it, briefly press another key or press two keys at once and, without releasing these keys, briefly press the third key. In this case, a certain action is performed.
Usually on the keyboard, the keys are indicated in both Cyrillic and Latin. To change the keyboard layout, i.e. to change the language, you need to use the key combination Shift + Alt or Shift + Ctr, depending on how you configured the keyboard settings. In the parameters you can add various languages. I will show you how to change the keyboard settings later.
If you look at the numbers located in the alphanumeric keyboard, you can see symbols on the keys.
The Shift key is used to enter these characters.
! is Shift+1, i.e. press the Shift key and, while holding it, click on the unit;
"" or "" - quotes S^2, instead of Shift I wrote S, and instead of + symbol ^ to make it shorter;
point in English language- the letter "U", a comma - the letter "B". In Russian and Ukrainian, a dot is a key to the left of the right Shift key, a comma is the same key, only with the Shift key pressed.
For Ukrainian keyboard layout:
i is the letter y;
ґ - key to the right of the left Shift key.
