Function            Tone - play a tone

  Syntax              void Tone(unsigned frequency, unsigned duration);

  Prototype in        sound.h

  Remarks             Tone() will play a tone of a specific frequency for
                      duration milliseconds. See sound.h for definitions
                      of common tones.

  Return value        returns nothing.

  See also            beep()

  Example             #include <sound.h>

                      main()
                      {
                           Tone(sA4s,2000u);
                           /* play A sharp for 2 seconds */
                      }