Tripp Lite 18in USB to Null Modem Serial Adapter FTDI w/ COM Retention M/F 18" - serial adapter - USB - RS-232
What is null modem? Null Modem cable vs Straight serial cable
Amazon.com: DTech DB9 RS232 Serial Cable Male to Female Extension Null Modem Cord Cross TX RX line for Data Communication (5 Feet, Black) : Electronics