Able to get Coordinator API and Router AT working together. The signal strength display was not updating properly. I think it’s due to the code to extract address and RSSI data from the message. The Serial callback was being called at the correct cycle so I’ll need to look at that.
I was not able to get a good connection with the Router in API mode. That needs to be done.
One trick with Coordinator hooking up to Processing was that it needed to be in AP mode 2. This was in the documentation. This makes me think that there is a related setting in the Router setup that needs to be researched. I found this which may be useful (ATAP2): http://beaststwo.org/xbee_api/index.shtml
Another issue is with power consumption. The 9V battery appeared to run out pretty quickly. That needs to be measured.
Found that there is a possibility of doing remote code uploads. That would be unbelievably cool and will need to research. Having to program by disconnecting the hardware serial lines is a pain.