It is central to the Bluetooth SIG's "3-in-1 phone" use case.
To do this the driver must know the proper identity of the peripheral.Note that devices are expected to provide some basic functionality using only the Bluetooth profile implementation, and that additional software loaded using the Device ID information should only be necessary for extended or proprietary features.It resides on top of the Bluetooth Core Specification and (optionally) additional protocols.While the profile may use certain features of the core specification, specific versions of profiles are rarely tied to specific versions of the core specification.A few examples illustrating possible uses of this information are listed below: 1.
In PC-to-PC usage models (such as conference table and file transfer), a PC may use this information to supplement information from other Bluetooth specifications to identify the right device to communicate with. A cellular phone may use this information to identify associated accessories or download Java apps from another device that advertises its availability. In PC to peripheral usage models (such as dial up networking using a cellular phone), the PC may need to download device drivers or other software for that peripheral from a web site.In these cases, it is impossible to connect certain A2DP headphones for high quality audio.The ATT is a wire application protocol for the Bluetooth Low Energy specification.Each A2DP service, of possibly many, is designed to uni-directionally transfer an audio stream in up to 2 channel stereo, either to or from the Bluetooth host. It includes mandatory support for the low-complexity SBC codec (not to be confused with Bluetooth's voice-signal codecs such as CVSDM), and supports optionally MPEG-1 Part 3/MPEG-2 Part 3 (MP2 and MP3), MPEG-2 Part 7/MPEG-4 Part 3 (AAC and HE-AAC), and ATRAC, and is extensible to support manufacturer-defined codecs, such as apt X.Some Bluetooth stacks enforce the SCMS-T digital rights management (DRM) scheme.This is designed for cordless phones to work using Bluetooth.