BLUETOOTH:

           The simplest and most common way for two hand held devices to communicate with each other is via Bluetooth. Bluetooth networking transmits data via low-power radio waves. It communicates on a frequency between 2.402 GHz and 2.480 GHz. This frequency band has been set aside by international agreement for the use of industrial, scientific and medical devices (ISM). Bluetooth devices send out weak signals of about 1 mill watt to avoid interference with other devices such as computers and cell phones. This low power, however, limits its range to 10 meters, but its signal can pass through walls so direct line of sight is not required.

           Another great advantage of Bluetooth is that it can connect up to eight devices simultaneously without interference. It use a technique called “spread-spectrum frequency hopping” which, put in simple words, means it keeps changing its frequency in the designated range and thus interference, if any, lasts for a fraction of a second and goes unnoticed.

            Like any wireless network, security is a concern with Bluetooth. The automatic nature of the connection which makes it easy to use can also be used against you by sending data without your permission. To avoid this, Bluetooth offers several security modes, and device manufacturers determine which mode to include in a Bluetooth-enabled gadget, the user has to decide whether to allow it. If you use the device quite often, you can mark the device as trusted and it will be able to exchange data without permission.