Vision manual page:23
J23/27=fader when automation is installed
1=ground
2=wiper
3 Top of fader
J25/28=Automation connector or fader connector when no automation is installed
1=Ground
2= VCA out
3=VCA in
4=Reference voltage
5=+5 volt (dependent upon VCA type)
J26/29=Pre Mute select
1/2=Mute active on aux pre fader setting
3/4=Mute not active on aux Pre fader setting