Sets up the source for tones that will appear on the PCjr's "Audio Out" or RF modulator.
Call with:
AH = 80H
AL = sound source
00H if 8253 programmable timer, channel 2
01H if cassette input
02H if "Audio In" line on I/O channel
03H if sound generator chip
Returns:
Nothing
Note:
This function is supported on the PCjr only.