Specifications
XBee®/XBee‐PRO®SERFModules
©2009DigiInternational,Inc. 46
The API transmit frame can include up to 128 bytes of data, which will be broken up into multiple
transmissions and reassembled on the receiving side. If one or more of the fragmented messages
are not received by the receiving device, the receiver will drop the entire message, and the sender
will indicate a transmission failure in the Tx Status API frame.
Applications that do not wish to use fragmentation should avoid sending more than the maximum
number of bytes in a single RF transmission. See the "Maximum RF Payload Size" section for
details.
Data Transmission Examples
Example 1: Send a transmission to the coordinator
Use the explicit transmit request frame (0x11) to send data to the coordinator. The 64-bit address
can either be set to 0x0000000000000000, or to the 64-bit address of the coordinator. The 16-bit
address should be set to 0xFFFE when using the 64-bit address of all 0x00s.
Suppose an ASCII "1" will be sent to the coordinator, addressed to destination endpoint 0xE8,
cluster ID 0x0011, and profile ID 0xC105. The explicit transmit API frame for this transmission
might look like the following:
7E 00 15 11 01 0000 0000 0000 0000 FFFE E8 E8 0011 C105 00 00 31 18
Notice the 16-bit address is set to 0xFFFE. This is required when sending to a 64-bit address of
0x00s.
Example 2: Send a broadcast transmission
This example will use the explicit transmit request frame (0x11) to send an ASCII "1" in a
broadcast transmission.
To send an ASCII "1" as a broadcast transmission, the following API frame can be used:
7E 0015 11 01 000000000000FFFF FFFE 5E 5E 1234 0109 00 00 31 B5
Notice the destination 16 bit address is set to 0xFFFE for broadcast transmission.
RF Packet Routing
Unicast transmissions may require some type of routing. ZigBee includes several different ways to
route data, each with its own advantages and disadvantages. These are summarized in the table
below.