Бопеее Before the invention of electromagnetic telephones, mechanical acoustic devices existed for transmitting speech and music over a distance greater than that of normal direct speech. The earliest mechanical telephones were based on sound transmission through pipes or other physical media.[1] The acoustic tin can telephone, or lover's phone, has been known for centuries. It connects two diaphragms with a taut string or wire, which transmits sound by mechanical vibrations from one to the other along the wire (and not by a modulated electric current). The classic example is the children's toy made by connecting the bottoms of two paper cups, metal cans, or plastic bottles with tautly held string.[1][2]

Among the earliest known experiments were those conducted by the British physicist and polymath Robert Hooke from 1664 to 1685.[1][3] An acoustic string phone made in 1667 is attributed to him.[4]

For a short period of time, acoustic telephones were marketed commercially as a niche competitor to the electrical telephone, as they preceded the latter's invention and didn't fall within the scope of its patent protection. When Alexander Graham Bell's telephone patent expired and many new telephone manufacturers began competing for customers, acoustic telephone makers quickly went out of business. Their maximum range was very limited, but hundreds of technical innovations, resulting in about 300 patents, increased their range to approximately a half mile (800 m) or more under ideal conditions.[2] An example of one such company was the Pulsion Telephone Supply Company created by Lemuel Mellett in Massachusetts, which designed its version in 1888 and deployed it on railroad right-of-ways.

Additionally, speaking tubes have long remained common, including a lengthy history within buildings and aboard ships, and can still be found in use today.