Thanks. I have started looking at the API. However, since I am sending from an Arduino to a Connectport X2, I can't have arduino code running on the Connectport (ZB Coordinator) to return the senders address.
I need to find a way to get the address from within the local board. Does that make sense?
Sure, use ATSH and ATSL to get the 64-bit address, or ATMY to get the 16-bit address. The latter is only unique within the network, but I'd think that'd be good enough for a lot of purposes.
PaulS also makes a good suggestion, I do something similar, only I use the XBee Node Identifier. I set a unique NI in each XBee, then the program interrogates it and inserts it into the transmitted data.