INT 1Ah,  80h (128)      Set Up Sound Multiplexer                        PCjr

Determines the source to be used for sound generation.

On entry:      AH         80h
AL         Sound source
00h - 8253 channel 2
01h - Cassette input
02h - "Audio in" line on I/O channel
03h - Complex sound generator chip (TI
76496)

Returns:       CF         Set if error; else cleared

                                                                          

Notes:         This service is available only for the PCjr. ATs,
XT-286s, and PC Convertibles will set the Carry
Flag, thus reporting an error state. Previous
machines will report unpredictable results
(including the state of the Carry Flag).

On power-up, the default sound source is the 8253
programmable-timer chip, via channel 2.


INT 1Ah, 80h (128) Set Up Sound Multiplexer PCjr