Towards the back of the PDF, there is a calibration routine. If your multimeter disagrees with the LCD display:
| Parameter | Specification | | :--- | :--- | | | XH-M452 | | Function | 2-Channel Audio Switch (1 Input to 2 Outputs OR 2 Inputs to 1 Output) | | Operating Voltage | DC 12V (Typical range 9V–14V) | | Current Consumption | <50mA (Depends on relay state) | | Channels | 2 (Stereo Left/Right) | | Switching Component | Signal Relay | | Switch Type | Momentary Push Button (Not Included) | | PCB Size | Approx. 55mm x 40mm | xh-m452 manual pdf