Adopts reliable ASIX AX99100 main control chip, stable signal transmission for long-term serial communication tasks; Single PCIe x1 slot expands four independent standard DB9 RS232 COM ports, no port resource conflict; Standard PCIe x1 interface, compatible with all PCIe x1/x4/x8/x16 motherboard slots, easy desktop installation; Built-in anti-surge and electrostatic protection circuit, adapts to industrial equipment monitoring and control scenarios; Full system compatibility with Windows, Linux and DOS, plug-and-play after driver installation