We are a church using a QU-24 tied to an AR2412. This has 12 mic lines that were run through the wall from mic jacks in the front of the room to a ‘sound’ closet near the back of the room when the building was constructed. We went with QU24 and AR2412 to give us some expansion capabilities beyond what we had originally.
We are finding that we need more inputs in the front of the room and do not want to run a lot of mic cables on the floor to the AR2412 or QU24. Additionally we are unable to run more wires through the wall back to the AB2412. Can we use the expansion port on the AR2412 to an AB168 to get more up front inputs? I realize that I can’t use all 24 inputs from the AR2412 as well as all the inputs from the AB168.
Thanks
DJH
You can indeed connect a ab168 of ar84 thru the expansion connector of the ar2412.
Richard
I have a AR2412 and AB168 and have done that many times with my QUPAC.
Keep in mind any stereo line inputs that you are not using on the mixer
can be routed to a mic input on a stage box, doing that can
get you a couple extra mic inputs at the mixer using the stereo input
channels.
Thanks. When I researched this in the manuals, all that was showing was an AR84 connected to the AR2412, and it supposedly only gave you three stereo inputs. So thank you all for your input and response! 
The model number of the stage boxes indicate the IO.
2412 has 24 inputs and 12 outputs.
168 has 16 inputs and 8 outputs.
84 has 8 inputs and 4 outputs.
Keep in mind the outputs on any combination of the boxes can
be patched in any combination of the mix outs on the board.
Such as you can mix 1 appear on any or all of the outputs
on any stage box at the same time.
Handy if you have a stage box on each side of the stage and need the
same mix at each side.