Protocol: LC default communication rate: 9600Bps; LC Communication Protocol: Data (1)----starting identifier (default: 0xA0) Data (2)----Switch address code (default: 0x01, identified as the first switch) Data (3)----Operation data (0x00 is "OFF", 0x01 is "ON") Data (4)----check code Example: TURN ON: A0 01 01 A2 TURN OFF: A0 01 00 A1 HOW TO USE: 1, plug the USB relay into the computer, install the CH340 to serial port chip driver; 2, open STC-ISP, SSCOM32 and other serial debugging software, select the rate of 9600, send "A0 01 01 A2" turn on relay in hexadecimal (hex) form; send "A0 01" in decimal (hex) 00 " TURN OFF relay; USB intelligent control switch. Onboard high-performance -controller chip. Board CH340 USB controller chip. Onboard Power LED and relay status LED. Onboard 5V, 10A / 250VAC, 10A / 30VDC relay, relay life long continuous pull 100,000 . Relay modules with overcurrent protection and freewheeling diode protection. colour:blue Material:PCB size:49.6*16mm Package Contents: 1 x USB relay module Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.