How to use computer to control your devices

 To use a computer to control (Power on/off) many devices, one may use a system like this.

1.  Connect a multi-channel Relay module to a computer via possibly RS485 interface. Something like this.

Modbus RTU 8-Channels Relay Module with RS485 Bus

2. Then use low voltage wire to connect a device via solid state relay to the multi-channel relay. Something like this:

3. Then create a program to manage the multiple channel relay to control device's power.

4. It may be necessary to have a converter for RS485 so that the multi-channel relay can be connected with a computer (PC)