737 EFIS

I'm planning on building one and on researching how to, I remembered Ian sisoms built one.Now he used cts 288 rotary encoders w/push to make connected to a bu 0836 x card to control for example the minimums switch/knob on the pmdg 737.From my understanding this effectivly gives you 3'key presses'or uses up 3 button connections on the card,lets say mins press(the push to make button)- b1 on the card,mins increase- b2 and mins decrease-b3 and that's all you can do with one encoder. but HA! the mins switch/knob has another key press and that is mins reset (or changing from baro to radio)QUESTION,how did Ian encorporate that key press into the encoder or did he just omit it,hard to believe considering Ians attention to detail. anyone else built one of these or knows how I would appriciat some help, thanks, john .