- Bluetooth is an energy efficient, low overhead communication protocol that's ideal for interdevice communications.
- Unlike infrared, Bluetooth doesn't require a line of sight.
- Depending on the implementation, Bluetooth can have a range of up to 100 meters.
- The specification of Bluetooth consists of a Foundation Profile Document and a Foundation Core Document.
- The protocol stack for Bluetooth consists of core protocols, cable protocols, and even adapted protocols.
- The transmitter operates around the 2.4 GHz frequency band.
- The data channel will change frequency, or hops, 1,600 times in a second, between the 79 allocated channels in the ISM band.
- Bluetooth utilizes a spread spectrum frequency hopping RF characteristic to ensure that independant networking operates when the other devices are in range.
- A piconet is formed when one or more devices open up a channel of communication.
- A piconet can have a master and up to seven slaves.
- Communication of the interdevice is based on the concepts of channels.
- All Bluetooth devices are capable of transmitting voice.
- The channel has a total capacity of 1 MB per second.
- There are two types of channels with Bluetooth - SCO (Synchronous Connection Oriented) and ACL (Asynchronous Connectionless).
- The SCO channels are time oriented, and are therefore primarily used for transferring time critical data such as voice.
- ACL channels are normally used for communicating data.
- Data contained in a packet can be up to 2,745 bits in length.
- In a single piconet, there can be up to three SCO links containing 64,000 bits a second each.
- To avoid collision and timing problems, SCO links are reserved slots that are set up by the master.
- The masters can support up to three SCO links with either one, two, or three slaves.
- The slots that aren't reserved for SCO links can be used as ACL links.
- The LMP (Link Management Protocol) will handle link level security, error corrections, and the establishment of communications links.
- The LMP packets will have priority over user packets that originate and form the L2CAP layer.
- The L2CAP layer will ensure an acceptable quality of service.
- No more than one ACL link can exist at the L2CAP layer.
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