StarTech.com 24in Internal USB Motherboard Serial Port Adapter

Add an RS232 serial port to your system using a spare USB header. The ICUSB232INT1 USB to RS232 serial adapter lets you add an RS232 port to any desktop system that is equipped with an available USB motherboard header.
Unlike standard USB to serial cables, this cable is designed for use inside the PC case, affording an entirely internal solution with no mess or extra adapters needed.
This compact and simple USB adapter offers a cost-effective solution that bridges the compatibility gap between modern computers and legacy serial peripherals.