Applications
The Bluetooth SIG defines many profiles for Low Energy devices: a profile is a specification for how a device works in a particular application. Manufacturers are expected to implement the appropriate specification(s) for their device in order to ensure compatibility. Bluetooth 4.0 provides low power conception with higher baud rate.
The GATT profile is a general specification for sending and receiving short pieces of data known as 'attributes' over an LE link. All current Low Energy application profiles are based on GATT.
Note that individual devices may implement more than one profile - e.g. one unit could contain both a heart rate monitor and a temperature sensor.
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