Wireless 802.15.4 ProXR Enhanced with UXP:

Wireless 802.15.4 Relay Controller with
UXP Expansion Port and XR Expansion Port

Take all the Power of the ProXR Series Relay Controllers...add a Digi Wireless 802.15.4 Compliant Interface: Remote Data Collection and Control is Effortless!

It works like this. Plug our Wireless 802.15.4 modem into the USB Port of your computer. The modem will mount as a COM port on your PC. Open the COM port and start sending data to the modem. The modem will forward your data to all Wireless 802.15.4 compliant devices within range (it is also possible to speak to a specific device when other controllers are in range).

This ProXR series controller offers wireless serial communications, requiring only a 12VDC Power Supply. Once powered up, the relay controller waits for a command. A command consists of a few bytes of data. Usually between 2 and 6 bytes. Once the command has been received, the controller processes the command, and sends you back ASCII character code 85 to signal the completion of your command.

Read More About Wireless 802.15.4 Communications