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. 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.