TEL is the abbreviation of Telephone in English and is not a trademark.

Telephone in English comes from the Greek τ?λε (tēle, meaning "far") and φων? (phōnē, meaning "sound"). The old translation is a telephone that can transmit Remote communication equipment with which sound is received.

As early as the 18th century, the word "telephone" existed in Europe, which was used to refer to a microphone strung with wires (a cup strung with wires). The emergence of the telephone is attributed to Alexander Graham Bell. The principle of early telephones is that the sound of speech is a composite vibration in the air, which can be transmitted to a solid body and transmitted through electrical pulses on conductive metals. ?Bell applied for a patent for the telephone in March 1876.

Extended information:

How the telephone works

Telephone communication is a method of transmitting language through the mutual conversion of sound energy and electrical energy and using the medium of "electricity". communication technology. The simplest form for two users to communicate is to connect two telephone sets with a pair of lines.

1. When the speaker picks up the phone and speaks into the microphone, the vibration of the vocal cords excites the air to vibrate, forming sound waves.

2. Sound waves act on the microphone, causing it to generate current, which is called voice current.

3. The voice current is transmitted along the line to the receiver of the other party's phone.

4. The function of the receiver is exactly the opposite of that of the transmitter - converting current into sound waves and transmitting them to people's ears through the air.

Baidu Encyclopedia-Tel

Baidu Encyclopedia-telephone