> 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/absolute-volume/qudelix-5k.md).

# Qudelix-5K

#### **Blue LED Behavior**

The **Blue LED** on the Qudelix-5K blinks whenever the device receives a command from the connected source device.

When **Absolute Volume Control** is supported, adjusting the volume on the source device (e.g., a smartphone) sends a **volume command** to the 5K. Upon receiving this command, the 5K processes it and briefly blinks the Blue LED to indicate **active communication** between the source device and the 5K.

***

#### **When Absolute Volume Is Not Supported**

If the source device does **not send volume commands** to the sink device (the 5K), the 5K does not receive any volume control information.\
In this case, the **Blue LED will not blink**, since no command is being transmitted from the source.

When Absolute Volume is not supported, the source device controls the playback volume by **scaling the digital audio signal** before transmission.\
To achieve the best sound quality, set the **source device’s volume to the maximum level** to preserve the original bit resolution of the digital signal.