问答题

Practice 4　　Bluetooth is the newest kid on the technology block, and it holds a lot of promise for the assistive technology industry. Named for a 10th Century King of Denmark who unified the kingdoms of Denmark and Norway, Bluetooth is a shot-range wireless communication specification that promises to improve and increase electronic access to a number of environments by overcoming some of the obstacles typical of current technology. Bluetooth technology will enable devices to communicate and transfer data wirelessly and without the line-of-site issues of infra red technology.　　So how does it work?　　Bluetooth devices search each other out within their given operational range. Unlike devices that are wired together, Bluetooth devices do not have to be aware of the capabilities or properties of the devices to which they will connect beforehand. Bluetooth devices have a built-in mechanism that lets each device identify itself as well as its capabilities as it connects into this new Bluetooth network. This dynamic network does have a controlling device that designates itself as the master for the connection. Its programming and the capabilities necessary for the given task determine whether or not a device can be a master. For example, a cell phone may act as a master device when connecting to a headset, an ATM, or an information kiosk. However, the same cell phone or headset may act as a slave device to the information kiosk, now acting as the master device, broadcasting emergency evacuation information. The cell phone and kiosk can function in either capacity depending on the required function and their programming.