Good afternoon, I spent the last few hours reading up on XBee 900Mhz Modules and APM problems.  I have come across various discussions on the symptoms and problems but no real definite answers.  Some people have modded the boards the Xbee's plug into, some people have soldered a bridge on the back of the APM and some people have suggested using another serial port on the APM entirely.  As you can see this is somewhat confusing. I would like to build a howto or something to help others.  I was wondering if someone could answer these questions;

1.  Are any physical modifications required to the APM.

2.  Are any modifications required to the XBee serial adapter which connects to the APM.

The problems that I am experiencing seem to be somewhat common. 

1.  Xbee modules talk to them self using the Digi tools, or standard serial port programs.

2.  Mission Planner cannot connect to APM via Xbee.  Mavlink Bad Packet Errors

3.  Terminal shows random characters.  ( Some people say this is the binary format of the Mavlink data)

My attempts at a resolution;

1.  Followed the proper HOWTO's to get these devices to communicate.  Here.

2.  Tried most baud rates, 9600, 38400, 57600, 115200 with 0 success

3.  Tried changing the SERIAL3_BAUD value in the APM to different values matching the modems configuration.

Any help would be appreciated,

Rick