This product is a PCI Express bus-supported card designed for extending RS-232C compatible serial communication functionality on your PC. It has 4ch RS-232C-standard serial ports. With a 128byte built-in FIFO buffer for transmission and reception of each channel, the product supports a baud rate of up to 921,600bps. Up to 16 cards can be mounted on a single PC and the range COM1 - COM256 can be set. It also comes with a Windows/Linux driver, which allows cards to be used as OS-standard COM ports.