【正文】 ERIn order to make a Bluetooth equipment can also be in connection even in a very low power state, Bluetooth stipulates three energy saving state: Park state, Hold state and Sniff state. The energy saving efficiency of these states declines one by one. The most monly used radio is Class 2 and users of power. Bluetooth technology is designed to have very low power consumption. This is reinforced in the specification by allowing radios to be powered down when inactive.The Generic Alternate MAC/PHY in Version HS enables the discovery of remote AMPs for high speed devices and tums on the radio only when needed for data transfer giving a power optimization benefit as well as aiding in the security of the radios.Bluetooth low energy technology, optimized for devices requiring maximum battery life instead of a high data transfer rate, consumers between 1/2 and 1/100 the power of classic Bluetooth technology.SECURITYMobility and open of Bluetooth system makes safety problems extremely important. Although the frequency modulation technique used by Bluetooth system has already provided a certain security, but Bluetooth system still need safety management to link layer and application layer. In link layer, Bluetooth system provides authentication, encryption and key management, and other functions. Each user has a Personal Identification Number (PIN), which will be translated into 128 bit link key for oneway or bothway certification. Once the authentication finished, link will use encryphon key to encrypt. The link layer security mechanism provides a great deal of certification schemes and a flexible encryption scheme (means allow the consultation of the length of password). This mechanism is very important when the equipments in munication are from different countries, because some countries will specify maximum password length. Bluetooth system will select the smallest maximum allowable password length of all equipments in the piconet. Bluetooth system also supports the high level of protocol stack in different applications of special security mechanisms. Bluetooth security mechanism builds trust relationship between devices relying on pins. Once this relationship established, these pins can be stored in the equipment, in order to connection more quickly the next time.ApplicationThe Bluetooth application can be divided into 4 main aspects: Home, Work, En route and Entertainment.HomeModern family home is so different with pervious. With the seamless improvement of modern technology, more and more people start home office, living more freely and efficiently. Moreover, they also extend the technology to other aspects more than family office, such as family life.By using the products of Bluetooth technology, people are able to get rid of the cables around the home office. Mouse, keyboard, printer, laptop, puter, earphone and speakers can be used in a PC environment wireless, which not only increase the office area of beauty, but also forinterior decorationandto provide morecreativefreedom. In addition, with mobile devices and home PC to be synchronous and share calendar information, uses can access the latest information everywhere, at all times.Bluetooth devices can not only make the home office easier, but also make home entertainment more convenient: You don’t have to put aside the guests, left alone to choose the music. Users can store 30 feet wireless control on a PC or Apple iPod audio files. Bluetooth technology can also be used in the adapter, allowing people share with friends by sending photos to the TV Bluetooth Headset from cameras, mobile phone and laptop. BT GO of ASUS is an perfect example of the Bluetooth technology which has the function of file sharing backup, puter performance realtime adjustment Bluetooth(BT Turbo Remote),Bluetoothmobileputersto shareInternet access(BT to Net),listening to music, remote control, synchronization scheduling personal management.Workpreviously, the office is usually in chaos for various wires tangled.Power cable for the device, connection between the puter and the keyboard, printer, mouse, and cables of PDA, all of them make a disorder work environment.In some cases, this will increase the risk of the office, such as the employee may be tripping over wires or cables around.However, with Bluetooth wireless technology, the office no longer exist messy wires, the whole office is like a machine, like an orderly and efficient operation.PDA can be synchronized with the puter sharing calendars and contact lists, puter peripheral devices can directly municate with employees through a Bluetooth headset when walking in the office answer the phone, all without wires.Not limited to the use of Bluetooth technology to solve the clutter of an office environment.Bluetooth enabled devices can also create instant network, allowing users to share presentations or other files without patibility or access restrictions.Bluetooth devices can easily set group meetings, through the wireless network to engage in dialogue with other offices, and deliver the ideas to the puter. Whether in a nonnetworked, or trying to hold a heated discussion, Bluetooth wireless technology can help users easily convene meetings, improving efficiency and enhancing creative collaboration.Currently, there are many products on the market are supported by Bluetooth connection from a wireless device to another device to transfer files. Products similar as eBeam Projection enable keep the record of the meeting wireless, and other devices are supported multistakeholder suggestions.In order to eliminate desktop clutter connection, wireless high office, Bluetooth wireless keyboard, mouse, and presentation equipment can streamline the work space. Simultaneously connecting PDA or cell phone to puter wirelessly can update and manage user39。s contact list and calendar timely and effective.Bluetooth also he