Bluetooth

Bluetooth – Connecting mobile phones to other devices without cables. Bluetooth specification is for a complete system from physical layer to application layer.

Piconets –The basic unit of a Bluetooth system is a piconet, which consists of a master Node and up to seven active slave nodes within a distance of 10 meters. Multiple piconets can exist in the same room and can even be connected via a bridge node.  Scatternet is  an interconnected collection of piconets.

In addition to the 7 slave nodes in a piconet, there can be up to 255 parked nodes in the net. A piconet is a centralized system with the master controlling the clock and determining which device gets to communicate in which time slot. All communication is between the master and a slave.

Applications - Here applications are called profiles.

• Generic access’s job is to provide a way to establish and maintain secure links between the master and slave.
• Service discovery profile is a protocol for discovering offered services.
• Serial port profile emulates a serial line and is especially useful for legacy applications that expect a serial line.
• Generic object exchange profile defines a client-server relationship for object movement . A slave can be either a client or a server. It’s a building block for other profiles.
• The LAN access profile allows a device to connect to a fixed LAN.
• Dial-up networking profile allows a notebook computer to connect to a mobile phone containing a built-in modem without wires.
• Fax profile is similar to dial-up, it allows wireless fax machine to send and receive faxes using mobile phones without wire between the two.
• The cordless telephony profile provides a way to connects the handset  and its local base station.
• Headset profile provides hands free voice communication
• Object push, file transfer, Synchronization profiles are for actually exchanging objects between two wireless devices. These could be business cards, pictures or data files.