ETYM Greek tele far off + phone sound.
1. An instrument that converts sound into signals that can be transmitted over distances and then converts received signals back into sounds; SYN. phone, telephone set.
2. Transmitting speech at a distance; SYN. telephony.
Instrument for communicating by voice over long distances, invented by us inventor Alexander Graham Bell 1876. The transmitter (mouthpiece) consists of a carbon microphone, with a diaphragm that vibrates when a person speaks into it. The diaphragm vibrations compress grains of carbon to a greater or lesser extent, altering their resistance to an electric current passing through them. This sets up variable electrical signals, which travel along the telephone lines to the receiver of the person being called. There they cause the magnetism of an electromagnet to vary, making a diaphragm above the electromagnet vibrate and give out sound waves, which mirror those that entered the mouthpiece originally.

To communicate or announce by telephone.