Tandy 1000 HX Technical Reference Manual page 408

Exit Conditions:
CX = high (most significant) portion of clock count
DX = low (least significant) portion of clock count
AL = 0 of the clock was read or written (via AH = 0,1) within
the current 24-hour period; othrwise, AL > 0
Set Time Of Day
Set (write) the time of day using binary format.
Entry Conditions:
AH = 1
CX = high (most significant) portion of clock count
DX = low (least significant) portion of clock count
Sound Multiplexer
Sets the multiplexer for audio source.
Entry Conditions:
AH = 80
AL = source of sound
00 = 8253 channel 2
02 = audio in
03 = complex sound generator chip
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