About Bluetooth Audio Protocols Supported By Mac OSX Leopard, iPad & 3.0 iPhones

Advanced Audio Distribution Profile (A2DP) defines how high quality audio (stereo or mono) can be streamed from one device to another over a Bluetooth connection; i.e. music streamed from a mobile phone to a wireless headset or car audio.

A2DP was initially used in conjunction with an intermediate Bluetooth transceiver that connects to a standard audio output jack, encodes the incoming audio to a Bluetooth-friendly format, then sends the signal wirelessly to Bluetooth headphones that decode and play the audio. Bluetooth iPod Dock adapters are an example of this.

1-Piece Bluetooth headsets often come with a microphone and support for the MONOPHONIC Headset (HSP), Hands-Free (HFP) and Audio/Video Remote Control (AVRCP) profiles supporting things like cell-phone call management, acting as a speaker-phone. There are select over-the-ear headsets that support a second earpiece on a short wire that can deliver A2DP stereo for those who wan't minimal weight for phone calls, but higher quality for music listening.

A2DP is designed to transfer a uni-directional 2-channel STEREO audio stream at a much higher quality than for voice, such as music from a Bluetooth enabled cell-phone, MP3 player - to a headset or Bluetooth car receiver. This profile relies on AVDTP and GAVDP. 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 , MPEG-2, MPEG-4, AAC, and ATRAC audio formats needed for truly high quality audio.

Mac OS X: As of version 10.5 Lepoard and Snow Leopard OSX includes native support for A2DP on Bluetooth-equipped Macs. Version 10.4 does not support A2DP, but software like the Softick Audio Gateway for Mac OS X also supports A2DP. The iPhone variant of OS X now supports A2DP, but only in version 3.0. So - more recent versions of the 3G iPhone, WiFi iPad and 3GS iPad tablet support Bluetooth stereo audio input and output as well.

Bluetooth Uses For Your Mac

Consumers seem to LOVE wireless in any gadget that supports it. But Bluetooth is finding much wider uses than headsets, wirelss speakers, keyboards and mice. There's many other computing applications that need to transfer small files or data at close range:

+ Wireless control of and communication between a mobile phone and a hands-free headset.

+ Wireless networking between PCs in a confined space and where little bandwidth is required.

+ Wireless communication with PC I/O devices, the most common being a mouse, keyboard and printer.

+ Transfer of files, contact details, calendar appointments, and reminders between devices with OBEX.

+ Test equipment, GPS receivers, medical equipment, bar code scanners, and traffic control devices.

+ For remote controllers where infrared was traditionally used.

+ Low bandwidth applications where higher bandwidth is not required and cable-free connection desired.

+ Internet access on personal computers or PDAs using a data-capable mobile phone as a modem.