dacVocPlay()

         Plays a file with VOC format by a parallel DAC

    Syntax:

         dacVocPlay( cFile [, nRate] ) -> lError

         cFile : The VOC file name.
         nRate : The frequency ratio. Default value is 12000 Hz.
                 Use this value for frequency changes.

    Description:

         Plays a file with VOC format by a parallel DAC.

    Return:

         A logic value indicating if the function finished without error

    Example:

         dacVocPlay( "Luna.Voc", 13224 )