In 1860, German scientist Philip Reiss (1834-1874) created a receiver and a transmitter that could transmit voices with the help of electricity.
	He created the transmitter by carving a beer cask into the shape of an ear, and used part of a pig's intestine to create an "eardrum." The vibrations of the eardrum were converted into electrical currents.
	The receiver was made of a electromagnet (sewing needle with a coil wrapped around it); when electricity passed through the coil, the electromagnetic currents passed through a violin string, creating sound.
	This device was named "telephone" from the Greek words "tele" (distant) and "phone" (voice). The device could only transmit extremely short words and phrases, and was therefore not practical.

Alexander Graham Bell (1847-1922) invented the first practical telephone. Bell, a phonetics expert, conducted research into telecommunications and on March 10, 1876, made the world's first phone call (using his experimental phone) when he held a conversation with his assistant, who was in a separate room.
The telephone that Bell invented was a single device comprised of a transmitter and receiver with only one hole for both purposes.
Bell's telephone featured a thin iron diaphragm that was placed extremely close to an electromagnet. When a person spoke, the person's voice would cause the diaphragm to vibrate; these vibrations generated an induction current, which was sent to the other person's telephone.
The process is reversed in order to reproduce the received sounds.
Bell's telephone was successfully used in October 1876 to make the first long distance, two-way telephone conversation between Boston and Cambridge, Massachusetts, a distance of 3 km. It was put on display at the Centennial Exhibition in Philadelphia the same year and became instantly famous. Electrical engineers at the time were unaware that complex, high-frequency oscillations could be converted into electronic signals, making telecommunication possible. Bell's advisor Moses Farmer (1837-1893), who also discovered two-way electronic signal communication system, once claimed that the telephone might never have been invented by Bell had he been a full-fledged electric engineer instead.