PCI-Express (PCIe) that provides two ports RS422/RS485. The PCIe interface allows a transfer rate of up to 250 Mb/s. It has two DB9-Male connectors on the metal bracket. The PCIe interface eliminates potential problems of conflict of IRQs. Allows operation 4-wire RS-422/485 and 2-wire RS485. Speed up to 921.6 kbps RS422/485 Compatible with Windows and Linux.