i need to ask about xbee packet size. is it there any minimum size for the packet of API.
i'm using Xbee S2 API mode AP1 however when i send below frame from router to coordinator the packet failed to arrive .
Packet : uint8_t payload[] = {'B',200,200,200,200};
However if i send :
Packet : uint8_t payload[] = {'B',200,200,200,200,200,200};
the packet arrived successfully .... weird :(
Test 3:
Packet : uint8_t payload[] = {'B',200,200,200}; 
the packet arrived successfully
Test 4: 
uint8_t payload[] = {'B',200,200};
the packet is failed to arrive :(
i don't know what is the problem
There isn't a minimum size, but the module does make use of a "packetization timeout" setting (ATRO) to decide when to send your data.  If you wait longer, you may find that the module sends the frame and it arrives at the destination.
I'm assuming you're using "AT Mode" even though you write "API Mode".  If you are in fact using API mode, please post more of your code, and perhaps include a link to the code library you're using to build your API frames.  Are you setting the length correctly?  Does the library expect a null-terminated string for the payload?  Try adding a 0 to the end of your payload array to see if that helps.
Xbee API packet is failing to arrive from router to coordinator