This half size card provides 2-industry standard 9 pin RS232 serial COM ports in a single PCI slot. By adding the optional LPT adapter cable, a parallel printer port becomes available. As PCI is fully Plug & Play compatible the operating system or BIOS automatically configures card ensuring conflict free installation. The UC-257 uses Brainboxes new industry leading UART BB16PCI958 and supports both 3.3V / 5V standards