Key benefits and how it helps Direct CTRL to MUTE linkage: The CTRL pin is normally connected to the Bluetooth MUTE pin, enabling seamless mute control between your Bluetooth module and the power amplifier board. This reduces the need for a separate mute circuit and simplifies integration. Flexible operation with simple configuration: The board ships in ACF1 mode by default for standard use. If you need CTRL mode, you can enable it with a simple hardware change by soldering off R5. No software setup required. Reliable, hardwarebased control: Because the mute control is provided through the CTRL and MUTE pins, response is fast and independent of software, improving reliability in applications where immediate muting is important. Clear compatibility and usage: Designed to work with standard Bluetooth modules that provide a MUTE pin, making it straightforward to integrate into existing audio projects. How it works Default state: The power amplifier board operates in ACF1 mode out of the box. CTRL mode activation: To use CTRL mode, remove the solder bridge on R5. This switches the board to CTRL mode, enabling CTRLtoMUTE control via the Bluetooth module. Pin functions: CTRL pin is intended to connect to the Bluetooth MUTE pin, enabling automatic muting behavior when the BT module signals mute. Use scenarios Home audio with Bluetooth input: Build a compact wireless speaker or integrated amplifier where muting is controlled by the Bluetooth source (for example, during calls or when muting is required). Car or portable audio projects: Create a dashboard or portable system that mutes the amplifier automatically when the connected Bluetooth device issues a mute signal, reducing audio leakage and enhancing user experience. DIY audio experiments and modular setups: Use default ACF1 mode for standard operation, or enable CTRL mode for projects requiring direct Bluetoothcontrolled muting, with a simple R5 modification. Notes The CTRLtoMUTE relationship relies on the Bluetooth module providing a MUTE signal; ensure your Bluetooth module's MUTE output is compatible with the board's CTRL input. Mode selection is hardwarebased: no software changes are needed, just a soldering adjustment on R5 to switch between ACF1 and CTRL modes.