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

   AH = 83h
   AL = volume (0=silence, 7=highest)
   CX = number of bytes to play
   DX = time between sound samples (multiples of 273 nanoseconds)
       only bits 11-0 used
   ES:BX -> sound data (array of 8-bit unsigned PCM samples)

Return: AH = 00h
   CF set if sound is busy
   CF clear if sound chip is free

Notes: this call returns immediately while the sound plays in the
     background; the sound chip is clocked at 3.57 MHz, with the low 12
     bits of DX specifying the clock divisor
   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"Tandy",INT 15/AH=91h