Check Device Manager under "Universal Serial Bus devices." If you see an "Unknown Device" or "IrDA USB Device" with a yellow exclamation, you need the legacy driver. Right-click → Update driver → Browse my computer → Let me pick → Select "Infrared" and choose "SigmaTel IR Adapter" if available.
Unlike modern Bluetooth, IrDA is strictly line-of-sight. The U2IrDA Mini has a narrow cone. Tape the dongle to a small block of wood or a flexible gooseneck clip. Align the two devices so they face each other like two people making eye contact. No more than 15 degrees off-axis. U2IrDA Mini 4 MBPS FIR USB IrDA 20
The name itself is a dense cluster of technical specifications. Let’s break it down: Check Device Manager under "Universal Serial Bus devices