Protocol: LC USB switch default communication baud rate: 9600 Bps. LC USB Switch 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 and install the CH340 serial port chip driver. 2. Open SSCOM32 or similar serial debugging software, set baud rate to 9600, and send "A0 01 01 A2" in hexadecimal format to turn on the relay; send "A0 01 00 A1" to turn off the relay. USB intelligent control switch with onboard high-performance microcontroller chip. Features CH340 USB controller chip. Includes power LED and relay status LED. Onboard 5V, 10A / 250VAC, 10A / 30VDC relay with long life of up to 100,000 cycles. Relay module includes overcurrent protection and freewheeling diode protection. Color: Blue. Material: PCB. Dimensions: 49.6 x 16 mm. Package includes: 5 x USB relay modules. Note: Light reflection and display differences may cause slight color variations between image and actual item. Measurement error allowed within +/- 1-3 cm.