USB Powered & Plug-and-Play: Connect directly to any USB port—no extra power supply required—for instant 4-channel relay control on Windows and Mac. Reliable Serial Interface: Features Silicon Labs CP2102 chipset; install driver once to create a virtual COM port for stable, high-speed communication. Simple AT Command & Python Integration: Control each relay with ASCII-formatted AT commands; sample Python scripts included to jump-start your automation projects. Wide Voltage Range & High Load Capacity: Safely switch AC 110–250 V or DC up to 30 V; supports up to 600 W per channel for industrial and home automation. About DSD TECH: Established in 2009, DSD TECH specializes in industrial connectivity solutions, delivering 80+ products (USB/RS232/UART/RS485/CAN) to 100,000+ global clients across automation and communication sectors. Every device comes with lifetime support and 1 year product replacement service. SH-UR04A is a 4-channel USB-powered relay module for Windows and Mac. Featuring the CP2102 chipset, it offers stable serial communication, AT command and Python control, and supports AC/DC loads up to 600W per channel—ideal for automation in industrial or home projects.