Audio Input Signal Selector Relay Board/Signal Switching Amplifier Board + RCA

Audio Input Signal Selector Relay Board/Signal Switching Amplifier Board + RCA L

Latching relay board 12vdc ( single pushbutton input to latch / unlatch relay )

7-24V Modbus Rtu 1/2/4 Channel Relay Module Switch input output RS485/TTL UART

Optocoupler / Photocoupling Isolation Board 6N137 5V NPN Input 3.3V~24V DC

DIY Board Relay Switch Signal Selector Audio Input Signal Amplifier Board

4-ch Modbus-RTU Relay Switch Module Signal input and output RS485 TTL Controller