StarTech.com Null-Modem Serial Cable - Extend your EGA monitor cable or mouse cable by 6ft - 6ft rs232 cable - 6ft db9 cable - 6ft db9 serial cable -6ft straight through serial
StarTech DB9 RS232 Serial Male to Male Null Modem Adapter NM9MM
What is the difference between Null Modem cable and Straight Through Cable...??? - One by Zero Electronics
What is null modem? Null Modem cable vs Straight serial cable
Null modem - Wikipedia
StarTech.com 10' RS232 Serial Null Modem Cable - Null modem cable - DB-9 (F) to DB-9 (F) - 10 ft - SCNM9FF Gray : Amazon.ca: Electronics