> For the complete documentation index, see [llms.txt](https://qudelix.gitbook.io/home/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://qudelix.gitbook.io/home/general/digital-audio-transfer.md).

# Digital Audio Transfer

Bluetooth A2DP and USB Audio Class (UAC) are the most representative digital audio transmission schemes.

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### **Terminology**

* **Source Device**: The device that sends the audio (Transmitter), such as a smartphone or PC.
* **Sink Device**: The device that receives the audio (Receiver), such as a Bluetooth DAC or USB DAC.
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### **Supported** Audio Format

When the receiver device connects to the source device, it sends the source device information about the supported audio formats, sample rates, bit resolutions, and codecs.

### Audio Format **Selection**

The source device selects one of the audio formats the receiver device supports for audio transmission.

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### Example #1 Bluetooth DAC

Information about supported audio formats is transmitted:

* 5K (Receiver) --> Android Smartphone
  * Supported codecs: SBC, AAC, aptX, aptX-Adaptive, LDAC
  * Supported sample rates: 44.1, 48, 88.2, 96 kHz

The smartphone selects one of the codecs and sample rates for transmission.