If using channels of playlist AB, DDO110 button spotted as 1 to 4 (matching the play option in cartstack mode), will not be used on these 2 tracks.
You can use these 8 buttons for a "relay" action
The setting of each of these relays is the same as the traditional GPI connection detection when playing a sound in AirDDO.
Setting done in the DDO12/DDO120 Interface tab of the setup. (See next chapter on how to configure these relays)