Communication A common example of a wireless mobile device that uses IR to establish a communication link is a television or stereo remote. You may point the remote at the television or stereo from across the room, and click buttons to turn the target device on or off and change channels. This is possible because the remote has an IR transmitter and its target device has an IR receiver that enables the one-way communication of data. This is done at UHF and microwave frequencies. This will allow the user to move around the office or even around the building and still maintain connection with the stationary system.
Satellites are also wireless systems that use RF to communicate.
The embedded chip at each end of the wireless communication runs software for interacting with the end user and managing the transmission. For example, a personal organizer could run software that lets the consumer connect through a PC to the Internet and download updates to its scheduling program. When the Java-based personal organizer application detects a button press requesting the latest update, it calls an open method and supplies as a parameter the URL address where the download resides on the Internet. The personal organizer and PC have IR transmitters and receivers, and so the URL information is transmitted to the PC using an IR communication link. When the transmission completes, the HTTP connection is closed and the IR or RF signal is turned off on the personal organizer.