Recommended pin connections

The only required pin connections for two-way communication are VDD, GND, DOUT and DIN. To support serial firmware updates, you must connect VDD, GND, DOUT, DIN, RTS, and DTR.

Do not connect any pins that are not in use. Use the PR and PD commands to pull all inputs on the radio high or low with 40k internal pull-up or pull-down resistors. Unused outputs do not require any specific treatment.

For applications that need to ensure the lowest sleep current, never leave unconnected inputs floating. Use internal or external pull-up or pull-down resistors, or set the unused I/O lines to outputs.

You can connect other pins to external circuitry for convenience of operation including the Associate LED pad (pad 28) and the Commissioning pad (pad 33). The Associate LED pad flashes differently depending on the state of the module to the network, and a pushbutton attached to pad 33 can enable various join functions without having to send serial port commands. For more information see Commissioning pushbutton and associate LED. The source and sink capabilities are limited to 6 mA on all I/O pads.

Only the programmable versions of these devices use the VREF pad (pad 27). For compatibility with other XBee modules, we recommend connecting this pin to a voltage reference if you want to enable analog sampling. Otherwise, connect to GND.