dacVocPlay()

         Reproduces a file with VOC format by a prallel DAC

    Syntax:

         dacVocPlay( cFile [, nRate] ) -> lError

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

    Description:

         Reproduces a file with VOC format by a parallel DAC.

    Return:

         A logic value indicating if the function finished satisfactorily

    Example:

         dacVocPlay( "Luna.Voc", 13224 )