One more question.....
I found this while browsinf for XBee series 2 options
Coordinator AT mode 1020
Coordinator API mode 1120
Router/End Device AT mode 1220
Router/End Device API mode 1320
Acc. to the discussion in this thread it is firmware 1241 for router/end device for znet 2.5
Now as znet 2.5 and xbee series 2 are same ( i think so) what is the difference in firmware 1241 and 1220