I am working in my bidirectional transmitter. i has built parts in plastic with my hobby cnc machine. it looks very technical device!!!i have not received PCB yet.i post some pictures of not finished assembly.We are testing XBee Pro Series 2 with ZB firmware now, it seems than 5 Kbytes/sec is possible. We publish transfer rate speed as soon as we finish testings.jlcortexnmine.com