The lower-layer Bluetooth protocols are normally embedded in the baseband module, and the host processor must support the upper-layer protocols (like file transfer). In other words, the RF/baseband solution provides the means to communicate with the host, but need to implement a connection interface, as well as any upper-layer protocols, to use applications supported by the final product.

The higher/upper layers of the Bluetooth technology called as the Bluetooth profiles and these are nothing but a set of protocols. These protocols are optimized for particular applications. In the case of file transfer between two devices, it requires interoperability among devices. Each of the linked devices needs to have similar applications ensures interoperability across a spectrum of devices.

The Bluetooth stack: It has the following components:

The radio frequency (RF) portion provides the digital signal-processing (DSP) component of the system, and the baseband micro controller processes these signals. The link controller handles all the baseband functions and supports the link manager. It sends and receives data, identifies the sending device, performs authentication, and determines the type of frame to use for sending a transmissions. The link controller also directs how devices listen for transmissions from other devices and can move devices into sleep state in order to save power.