Int 1A Fn 83  - Tandy 2500, Tandy 1000l Series - Start Playing Digital So  [s]

   AH = 83h
   AL = volume (0=lowest, 7=highest)
   CX = number of bytes to play
   DX = time between sound samples (multiples of 273 nanoseconds)
   ES:BX -> sound data (array of 8-bit PCM samples)

Return: ???

Notes: this call returns immediately while the sound plays in the
     background
   The sound data pointed to by ES:BX probably shouldn't cross a 64k
     boundary.  The BIOS appears to call INT 15/AX=91FBh when the sound
     device underflows to allow another INT 1A/AH=83h for seamless
     playing of long sounds.

See Also: AH=84h,INT 15/AH=91h