Give the definitions to the following terms

letter quality printer-
печатающее 
устройство с типографским качеством 
печати 
an ink jet printer –струйный 
принтер 
computational [kɒmpjʊˈteɪʃnəl]-
вычислительный 
to be of use to -быть полезным
1. Read and translate the text
A peripheral is a device that performs input, output or storage functions and is 
connected to CPU. In order for the computer to be of use to us, there must be some 
types of mechanism for entering data into the computer for processing. Devices 
which allow the task of data entry to be performed are called input devices. 
Input we use to perform the two basic computational tasks: data entry and issuing 
commands. The most widely used input device is the keyboard, which was adapted 
from the typewriter. The keyboard itself doesn’t contain any mechanism for 
creating printed pages. Each time a key on the keyboard is pressed, an electronic 
signal is sent to the system unit indicating which key was pressed. The system unit 
and the software interpret this signal and take the appropriate action. 
Some keys are added to terminal keyboards to fulfill special functions. The most 
important of these is the RETURN or ENTRY key. This is pressed by the user to 
indicate to the computer, by the sending of a special code, that the typed line is 
complete and that the computer can now analyze it. Other keys that may be present 
include a delete key which when pressed deletes the character just typed, special 
function keys that can be used for special purpose by different programs and one 
marked CONTROL or CTRL which also has a particular function when used with 
other keys. Some keyboards may also have a numeric keypad to the right of the 
typewriter keyboard. This may be of help when entering numeric data. 
There are three keyboard layouts. The first is the standard IBM-PC keyboard. The 
central portion of the keyboard consists of the alphanumeric keys, that there are ten 
function keys (labeled F1 – F10) on the top side of the keyboard, and there is a 
numeric keypad, much like that found on a calculator, on the right side of the 
keyboard. 
The function keys are keys which send special signals to the system unit. The 
effect of pressing a given function key will depend on the software which is 
currently in use. 
The numeric keypad is useful when numeric data must be entered into the 
computer. The numeric keypad serves two roles. The 1st role is the digits, decimal 
points and addition and subtraction signs are active. The 2nd role is the key of the 
keypad are used to control the small blinking box or line on the screen which 
shows the user where the next typed character will be displayed. This line is known 
as the cursor. The cursor control keys are the arrows (left, right, up and down), 

PgUp (page up), PgDn(page down), Insert and Delete. But there are several types 
of pointing device that are used to move the cursor and usually work in 
conjunction with the keyboard. The most common pointing device is the mouse, so 
called because it slides over the desktop and has a wire or ‘tail’ attached to the 
computer.
When referring to hardware, a scanner or optical scanner is a hardware input 
device that optically "reads" and image and converts it into a digital signal. For 
example, a scanner may be used to convert a printed picture, drawing, or document 
(hard copy) into a digital file which can be edited on a computer. 
Another pointing device is a trackball, which performs like a stationary upside-
down mouse. A joystick is another pointing device, one that is usually associated 
with playing computer games.
An output device is a piece of computer hardware that receives data from a 
computer and then translates that data into another form. That form may be audio, 
visual, textual, or hard copy such as a printed document.
There are four different 
categories of output device: visual, data, print, and sound. 
Monitors and printers are two of the most commonly used output devices used 
with a computer. Most computer outputs come in two forms: text and graphics. 
Printers are output devices which produce hardcopy. Printers come in all kinds of 
shapes and sizes, with varying capabilities and mechanisms for printing. There are 
different types of printers: a letter quality printer and a laser printer,
an ink jet 
printer. 
A laser printer provides high-quality non-impact printing and offers the highest 
quality texts and graphics printing for the desktop. A letter quality printer allows 
the production of documents with a high quality of printing at a relatively low cost. 
Like lasers, Ink jet printers are able to print many different types of fonts and 
graphics. 
The key distinction between an input device and an output device is that an input 
device sends data to the computer, whereas an output device receives data from the 
computer. 

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