Crossover or "Null Modem" vs. Straight Through Serial Cable - Decisive Tactics, Inc.
DB9pin Female to USB RS232 Null Modem Cable for Two DTE Device Communication Dsub 9pin to USB2.0 NMC|Computer Cables & Connectors| - AliExpress
DTech DB9 RS232 Serial Cable Male to Female Extension Null Modem Cord Cross TX RX line for Data Communication (10 Feet, Black)
Should I Use Null Modem or Straight Through Serial Cables? - NI
Null-Modem Serial Cables
Startech .com 2m Black DB9 RS232 Serial Null Modem Cable F/FConnect your serial devices, and transfer your files2m DB9 Null Modem Cable... SCNM9FF2MBK - Corporate Armor
Building the Null Modem Cable
Amazon.com: SF Cable, 6 ft DB9 F/F Null Modem Cable RS232 : Electronics
3ft (0.9m) Serial RS232 DB9 Null Modem Cable with Low Profile Connectors M/M - In-Wall CMG-Rated | Serial RS232 | Computer Cables | USB and PC