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 highly similar 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 electrical 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.