Star Tech. com 24in Internal USB Motherboard Header to 2 Port Serial RS232 Adapter The ICUSB232INT2 USB to serial adapter lets you add 2 RS232 ports 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.