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A computer is a machine that uses electricity to process and store data. It has input and output. It's divided into hardware (physical parts) and software (programs) -
It's the long-distance transmission of written messages without physical transport of letters. A telegraph sends electric pulses in a special code, composed from short and large marks. Usually, amateur radio operators use Morse code. -
It's a telecommunication device that allows 2 or more users to converse. The telephone converts the sound into electronic signals. The receptor of that signals convert them back into sound. -
Radio is a way to send electromagnetic signals over a long distance, to deliver information from one place to another. A machine that sends radio signals is called a transmitter, while a machine that "picks up" the signals is called a receiver or antenna. A machine that does both jobs is a "transceiver". -
It's a machine with a screen or set of lenses. Televisions receive broadcasting signals and change them into pictures and sound. The word "television" comes from the words tele (Greek for far away) and vision (sight). -
A tablet computer (sometimes called a tablet) is a type of computer that can be carried easily. Unlike a laptop it has no physical keyboard or trackpad, though users sometimes add those things. Users control a tablet mostly by using its touchscreen with multi-touch technology similar to a smartphone -
A mobile phone is a portable telephone that can make and receive calls over a radio frequency link while the user is moving within a telephone service area.