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Chapter 9. Networking: Wired and Wireles... > Project 9.1. Become More Familiar wi... - Pg. 228

228 Electronics Explained: The New Systems Approach to Learning Electronics Don 't forget that wireless Internet connectivity can also be achieved by using the regular cell phone networks. You can purchase a data modem that plugs into your laptop USB connector on a PC. This modem connects you just as it would a cell phone to your cellular network. From there you can use the 3G data service to connect to the Internet, access email, or perform other networking operations. ISM-BAND RADIOS The industrial-scientific-medical (ISM) band has been mentioned before. This comprises a group of frequencies or bands set aside for unlicensed data trans- mission over short ranges. The main application is telemetry monitoring and remote control. The U.S. frequencies are 13.56 MHz, 315 MHz, 433 MHz, and 902 to 928 MHz, with 915 MHz the most common. In Europe, 868 MHz is an unlicensed frequency. Transmitters and receivers are tiny single ICs with power levels from about 1 mW to 1 watt. Modulation is usually ASK/OOK or FSK. Data rates are low from a few kbps to usually no more than 100 kbps. Some typical applications are garage door openers, remote keyless entry for vehicles, remote thermometers, medical telemetry, remote-controlled toy cars and boats, and sensor reading in industrial applications. Range is no more than a hundred feet or so, but longer ranges to several miles can be achieved with higher antennas. Project 9.1 Become More Familiar with Wireless Data Protocols You may want to find more information on the most popular short-range wireless data methods. The following websites are recommended. And you may want to do a general Internet search with Bing, Google, or Yahoo!. Wi-Fi: www.wi-fi.org Bluetooth: www.bluetooth.com ZigBee: www.zigbee.org General sites: www.palowireless.com, www.howstuffworks.com The Wikipedia entries are also quite good.