1. Onboard stable MCU and MAX485 level conversion chip 2. Communication protocol: Support standard Modbus RTU protocol 3. Communication interface: Support RS485/TTL UART interface 4. Communication baud rate: 4800/9600/19200, default 9600, support power off 5. Optocoupler input signal range: DC3.3-30V (this input cannot be used for relay control) 6. Output signal: Relay switching signal, support manual, flash, flash mode, the flash/flash delay base is 0.1s, the longest flash/flash time can be set to 0xFFFF*0.1S=6553.5S 7. Device address: range from 1 to 255, default 255, support power-off save 8. Baud rate, input signal, relay status, device address can be set by software/command 9. Built-in 4 relays 5V, 10A/250V AC 10A/30V DC, can be activated 100,000 times continuously, with diode overflow protection and short response time 10. Onboard relay switching indicator light 11. Power supply voltage: DC7-24V, supports 5.08mm DC jack/power terminal, with input anti-reverse connection