Tendzone TYCHO T 1212/CA - Manual (Page 23)

As is shown in the above chart, the audio matrix will load Scene 2 automatically when the level of GPIO input channel 1 is
changed from low to high.
b) Mixer Setting
When the GPIO Channel is input 2, the mixer setting should be selected as the Control Type. As is shown in the chart, when
the level of GPIO input channel 2 is changed from low to high, the sound mixing contacts corresponding to input channel 2
and output channel 5 will be opened, and the signals of input channel 3 will be mixed and transmitted to output channel 5
and then the signals will be output. If the trigger type is trigger mode 4 (Falling edge of the open, rising off), the contacts
corresponding to the input channel 3 and output channel 5 of the key sound mixer will be closed when electrical level of
the pin of GPIO input channel 2 is changed from low to high.
c) Volume Setting