9 Pin DB9 Serial RS232 NULL Modem High Speed Shielded Cable 1m
Null modem - Wikipedia
FTDI Chipset Cross Wired USB Serial DB9 FT232R USB RS232 Null Modem Cable Pc Control TV Cable (Null Modem (laptop pc with usb communicate with destop pc(with DB9 com port)): Amazon.co.uk: Computers
Null modem cable Amiga-PC - Amiga Shop
RS PRO Female 9 Pin D-sub to Female 9 Pin D-sub Serial Cable, 5m | RS
File:D9 Null Modem Wiring.png - Wikipedia
RS232 Serial Null Modem Cable, Crossover - DB9 Cables & DB25 Cables | StarTech.com United Kingdom