Add two RS232 and two RS422/485 serial ports to your PC through a PCI-Express expansion slot 4 Port PCI Express PCIe Serial Combo Card 4 port (2 x RS232, 2 x RS422/485) serial combo card PCI Express RS485 / PCIe RS485 / PCI Express RS422 / PCIe RS422 serial combo card Dual Profile PCIe serial card adapter with breakout cable RS232 data transfer rates up to 460 Kbps PCIe serial combo card supports 2-Wire / 4-Wire RS485 modes Compliant with PCI-Express Specification 1.0a