Using an 8:3 encoder to take 8 switch inputs

So I plan to implement this 8:3 encoder : http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=296-8233-5-ND
I want some buttons to use to make this work. Do I want an off-mom or on-mom? I’m not sure what the difference is…:-/

It really depends on what your purpose with the buttons are.

Off - mom means that the button in one position is off (yeahh right :-) ) and in the other position (mom = momentary) is on as long as you hold it there, when you let go it jumps back to off.

If you need a button that is either on or off and stays in one of those states don't get a button with "mom" or "momentary" in it get one like on - off or on -off - on.

But it all comes down to what you want to achieve.