User's Guide

Operation Maximum payload
XBee/XBee-PRO S2C 802.15.4 RF Module User Guide
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Maximum payload summary tables
The following table indicates the maximum payload when using transmit compatibility with the Legacy
802.15.4 module (S1 hardware).
Encryption
Enabled Disabled
95 B 100 B
The following table indicates the maximum payload when using the application header and not using
encryption.Increment the maximum payload in 2 bytes if you are not using the application header.
Destination Address
Source Address Short Long
Short 114 B 108 B
Long 108 B 102 B
The following table indicates the maximum payload when using the application header andusing
encryption.Increment the maximum payload in 4 bytes if you are not using the application header.
Destination Address
Source Address Short Long
Short 101 B 95 B
Long 101 B 95 B
Work with Legacy devices
The Legacy 802.15.4 module (S1 hardware) transmits packets one by one. It does not transmit a
packet until it receives all expected acknowledgments of the previous packet or the timeout expires.
The new XBee/XBee-PRO S2C 802.15.4 RF Modules enhance transmission by implementing a
transmission queue that allows the device to transmit to several devices at the same time. Broadcast
transmissions are performed in parallel with the unicast transmissions.
This enhancement in the XBee/XBee-PRO S2C 802.15.4 RF Module can produce problematic
behaviorunder certain conditions if the receiver is a Legacy 802.15.4 module (S1 hardware).
The conditions are:
n The sender is a XBee/XBee-PRO S2C 802.15.4 RF Module, and the receiver is a Legacy 802.15.4
module.
n The sender has the Digi Header enabled (MM = 0 or 3) and RR (XBee Retries) > 0.
n The sender sends broadcast and unicast messages at the same time to the Legacy 802.15.4
module without waiting for the transmission status of the previous packet.
The effect is: