Bluetooth
Bluetooth is a low cost, low power, radio interface standard for wireless communication over short distances. It’s an open standard for allowing intelligent devices to communicate with each other. This allows any sort of electronic equipment (from computers and cell phones to keyboards and headphones) to make its own connections, without wires, cables or any direct action from a user. It could allow for replacing many propriety cables that connect one device to another with one universal radio link.
Please note that Bluetooth was originally conceived as a cable replacement technology providing short-Range Wireless Solutions with open specifications, voice and data capability.
Why Bluetooth?
Whenever two devices need to communicate with each other, they have to agree on a number of points before the communication can begin. The first point of agreement is physical: Will they talk over wires, or through some form of wireless signals? If they use wires, how many are required? Once the physical attributes are decided, there are other questions such as – How much data will be sent at a time? All of the devices in an electronic discussion need to know what the bits mean and whether the message they receive is the same message that was sent. This means developing a set of commands and responses known as a protocol. But Bluetooth offers an obviation to this rule. So, Bluetooth is essentially an OPEN networking standard that works at two levels viz. Physical and Protocol.
Bluetooth networking transmits data via low-power radio waves. It communicates on a frequency of 2.45 gigahertz (actually between 2.402 GHz and 2.480 GHz, to be exact). This frequency band has been set aside by international agreement for the use of industrial, scientific and medical devices (ISM).
Does Bluetooth interfere with other systems?
No. Bluetooth devices avoid interfering with other systems is by sending out very weak signals of about 1 milliwatt. By comparison, the most powerful cell phones can transmit a signal of 3 watts. The low power limits the range of a Bluetooth device to about 10 meters (32 feet), cutting the chances of interference between computer system and portable telephone or television. Even with the low power, Bluetooth doesn’t require line of sight between communicating devices.
What is spread-spectrum frequency hopping?
Frequency hoping is a technique for spread spectrum wireless signal transmission. Bluetooth can connect up to eight devices simultaneously, with all of those devices in the same 10-meter (32-foot) radius, but still these devices don’t interfer with each other. For this, Bluetooth uses technique called spread-spectrum frequency hopping that makes it rare for more than one device to be transmitting on the same frequency at the same time.
What is Bluejacking?
Since, Bluetooth is a radio wireless technology that allows computers, cell phones, laptops, etc. to exchange or talk to each other in a limited range. Hijacking via Bluetooth is called Bluejacking. It refers to sending unnecessary and anonymous messages by using bluetooth enabled devices as a contact. In order to carry out bluejacking, both devices should be bluetooth enabled and should be within 10 metres of each another. Phone owners who receive bluejack messages should refuse to add those contacts to their address book.