Phone - Navo

• First patented in 1876 by Alexander Graham Bell and further developed by many others, the telephone was the first device in history that enabled people to talk directly with each other across large distances.
• Telephones rapidly became indispensable to businesses, government, and households, and are today some of the most widely used small appliances.
• The word telephone has been adapted into the vocabulary of many languages. It is derived from the Greek: τῆλε,tēle, "far" and φωνή, phōnē, "voice", together meaning "distant voice".
• The essential elements of a telephone are a microphone (transmitter) to speak into and an earphone (receiver) which reproduces the voice of the distant person.
• A land-line telephone is connected by a pair of wires to the telephone network, while a mobile phone, such as a cellular phone, is portable and communicates with the telephone network by radio transmissions.
• Along with the microphone and speaker, additional circuitry is incorporated to prevent the incoming speaker signal and the outgoing microphone signal from interfering with each other.