INT 66 - DIGPAK - SET PLAY MODE                                                 
	AX = 0698h
	DX = playback mode
	    0000h 8-bit PCM
	    0001h 8-bit stereo PCM
	    0002h 16-bit PCM
	    0003h 16-bit stereo PCM
Return: AX = status
	    0000h command ignored
	    0001h mode set