| SW1 Position | Function | |--------------|----------| | 1: ON | RS-485 mode (default) | | 1: OFF | RS-232 mode (requires restart) | | 2: ON | Enable 120-ohm termination resistor (RS-485 only) | | 3: ON | Factory reset protection (must be OFF to reset) |
: Shows real-time CO concentration (ppm). It typically displays "0" unless CO levels exceed 20–30ppm. 3. Alarm Response Patterns Sound Pattern Visual/Display CO Gas 4 quick beeps, 5s silence Red LED flashes; LCD shows PPM Smoke Continuous "di-di-di" sound Red LED flashes; LCD shows "0.00db/m" Low Battery Single chirp every 30-40s Red LED flashes; LCD shows "Lb" Fault Double chirp Yellow LED flashes; LCD shows "Err" 4. Maintenance & Testing jkd-512com user manual
