The OX12PCI840 is a PCI Parallel Port controller from Oxford Semiconductor (now part of Microchip Technology). The OX12PCI840 is used to add parallel ports to a computer via a PCI slot. Parallel ports were traditionally used to connect printers, scanners, and other peripherals before being largely replaced by USB and other modern interfaces. This particular chip, the OX12PCI840, supports Enhanced Parallel Port (EPP) and Extended Capabilities Port (ECP) modes, offering faster data transfer rates compared to traditional Standard Parallel Port (SPP) mode.