PCI-E 4-port RS232 serial port card.; Expand 4 independent 9-pin standard serial ports, like the built-in serial port data interface.; Designed for POS and ATM applications, and a smart choice for industrial automation system integrators; The four RS232 serial ports of the riser card can support communication speeds up to 250Kbps and provide modem control to ensure compatibility with various peripheral serial devices.; Stable and effective control of data loss. Support hot swap.Support multiple systems: for windows7/8/10/LINUX. Support a variety of mainstream operating systems.