StarTech.com NM9MF DB9 RS232 Serial Null Modem Adapter, DB 9 (M) to (F)

Zoro Tools

Startech DB9 RS232 Serial Null Modem Adapter MF This Null Modem Cable Adapter features one DB9 male and one DB9 female connector - a cost-saving way to convert a straight through cable into a null modem cable. The DB9F Null modem adapter is backed by lifetime warranty and free lifetime technical support.

Amazon

Null modem adapter DB-9 (M) to DB-9 (F) A cost-effective way of converting a straight through cable into a null modem cable Easy to use and intall Backed by StarTech.com's lifetime warranty for P/N: PCI2S232485I