Bluetooth is a form of short-range wireless communications technology that is simple and easy to use, secure, and found in an increasing array of devices. Literally billions of devices ranging from cell phones, tablets and computers to home entertainment products, game consoles and medical devices. The reason Bluetooth was created was to replace the cables connecting devices, while maintaining high levels of security.
Bluetooth technology was developed around three main criteria: robustness, low power, and low cost. By requiring manufacturers and developers of compatible devices to adhere to a uniform Bluetooth Specification a wide variety of devices are able to connect and communicate with each other.
“Pairing” refers to when two Bluetooth enabled devices connect to each other. Because of its features and its global acceptance, any Bluetooth enabled device, in almost location anywhere in the world, can connect to other Bluetooth devices as long as they are located relatively close to one another.
When Bluetooth devices connect to each other wirelessly they form a short-range temporary network that is called a “piconet”. These devices can be setup by the user to automatically connect or disconnect to these piconets at any time, whether on command or by simply moving in and out of the range of the piconet’s wireless range.
Each device in a piconet can communicate simultaneously with up to seven other devices within that same piconet. Each device can also belong to several piconets at the same time. This means Bluetooth devices can connect to each other in virtually an infinite number of ways.
A key strength of Bluetooth wireless technology is the ability to handle data and voice transmissions at the same time. Bluetooth can be used to create devices that will perform a near limitless variety of tasks. Good examples would be hands-free headsets for voice calls, printing and fax capabilities, synchronization of PCs and mobile phones, device controllers for video games, remote access to environmental controls, and more. Bluetooth promises to be at the very heart of achieving the “Internet of Things”, where almost any device in our day-to-day lives can be accessed from anywhere in the world and controlled wirelessly through the internet.
Bluetooth Core Specification:
Unlike other wireless standards the Bluetooth Core Specification provides developers with both link layer and application layer definition in order to support both data and voice applications. For more information visit the Bluetooth.org website (some sections of the site require a password which can be obtained by becoming a member of the Bluetooth Special Interests Group, or BSIG).
The Bluetooth wireless signal operates in the unlicensed industrial, scientific and medical (ISM) band, between the 2.4 to 2.485 GHz range. The 2.4 GHz ISM band is available and unlicensed in almost all countries. Bluetooth makes use of a spread spectrum, frequency hopping, full-duplex signal at a nominal rate of 1600 hops per a second. Because it can detect other signals within its operating spectrum it can avoid them, allowing for a minimum of interference from other wireless signals that may be already exist in the immediate environment. By using adaptive frequency hopping, otherwise known as AFH, it can constantly shift from one frequency to the next and make it very difficult for hackers to intercept or corrupt the signal. This adds an extra layer of security for the users of an enabled device.
The effective range of Bluetooth wireless technology depends on its application. The Core Specification requires a minimum range of 10 meters, or just over 30 feet. However, there is no predetermined limit and manufacturers can modify the range to support the how their application will be used.
Bluetooth devices are typically rated as being of one of three Classes which gives an indication of both their range and their power consumption:
Class 3: Has a range of up to 1 meter, or 3 feet
Class 2: Has a range of 10 meters, or approximately 33 feet (most common class found in mobile devices)
Class 1: has a range of 100 meters, or just over 300 feet (primarily used in industrial applications)
The most commonly used signal is Class 2. It uses a mere 2.5 mW of power. Since most application are battery powered, Bluetooth technology is designed to have very low power consumption. This is reinforced in the specification by allowing Bluetooth radios to be power down when inactive for certain periods of time.
Bluetooth Low Energy technology, optimized for devices requiring maximum battery life instead of a high data transfer rate, consumes between 1/2 and 1/100 the power of classic Bluetooth technology.
It is because of these low power specifications that Bluetooth is widely considered to be the ideal wireless solution for devices that are meant to be safely used on or near the human body, especially over extended periods of time.