At this point in time, I have installed the keyboard and both PCBs on a sheet of PVC which I used to make a special cover for the phone. This allows me to test out the complete system in a practical manner without having to modify the phone at all. A switch on the side cuts off the power to the chip and will be connected to the slider in the final build to switch on the keyboard only when it is extended. The red and green LED's are indicators for ALT and Caps Lock respectively (they are driven directly by the SK5126 encoder which is another great reason to use that chip).