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2CH RS232 Relay for PC UART COM Serial Port


2CH RS232 Relay for PC UART COM Serial Port


If you have any questions on this product please feel free to contact us.

*Disclaimer: The images are merely illustrative.

Power input: DC 12V.
Power indicator: LED lights ;
Output indication: relay output with LED indicators, easy to see working status of the relay ;

Communication protocol: UART protocol communication, baud rate 9600kpbs, 8 data bits, one stop bit, no parity. Each data frame contains eight bytes. Two-way data transmission.
Baud rate 9600kbps, 8 data bitsone stop bit, no parity. Each data frame contains eight bytes..
PCB Size : 71x47mm

1 Control commands

1. Reading statusreading the satus of the relay (on/off)

0x55 0x56 0x00 0x00 0x00 0x00 0x00 0xAB


2. Relay open (issue this command ,Relay open , COM connect to NO )

Channel 1 :0x55 0x56 0x00 0x00 0x00 0x01 0x01 0xAD

Channel 2 :0x55 0x56 0x00 0x00 0x00 0x02 0x01 0xAE


3. Relay close (issue this command ,Relay close , COM disconnect NO and COM connect to NC )

Channel 1 :0x55 0x56 0x00 0x00 0x00 0x01 0x02 0xAE

Channel 2 :0x55 0x56 0x00 0x00 0x00 0x02 0x02 0xAF

4. Relay toggle(Relay status reversal,if COM connect to NO,this commands will Disconnect COM to NO and Reverse COM connect to NC,and vice versa

Channel 1 :0x55 0x56 0x00 0x00 0x00 0x01 0x03 0xAF

Channel 2 :0x55 0x56 0x00 0x00 0x00 0x02 0x03 0xB0


5. Relay momentary(Relay COM connect to NO,disconnect after 200MS )

Channel 1 :0x55 0x56 0x00 0x00 0x00 0x01 0x04 0xB0

Channel 2 :0x55 0x56 0x00 0x00 0x00 0x02 0x04 0xB1

Once issue a command, will have a return fame , 7th byte of return fame mean the satus of realy .

2 return command


1、Return relay open(return this command,mean COM connect to NO )

Channel 1 : 0x33 0x3C 0x00 0x00 0x00 0x01 0x01 0x71

Channel 2 : 0x33 0x3C 0x00 0x00 0x00 0x02 0x01 0x72


2、Return relay close(return this command,mean COM disconnect NO and COM connect to NC )

Channel 1 : 0x33 0x3C 0x00 0x00 0x00 0x01 0x00x72

Channel 2 : 0x33 0x3C 0x00 0x00 0x00 0x02 0x00x73

Remote control, remote measurement system; 
Wireless meter;
Smart Home,Home Automation ,Wiser Home;
Access control ;
Identification system;
Data collection; 
IT household appliance;
Intelligence household appliance;
Baby monitoring system;


Typial application :
1 - DC 12V control circuit,Wiring diagram below. "LOAD" may be LED lights, fans, motors and other DC 12V equipment


2 - DC 1-48V OR AC 85-265V control circuit,Wiring diagram below(Note:If not DC 12V load, need another DC 12V power supply). "LOAD" may be LED lights, fans, motors and other DC AC equipment




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