Gender changer D-Sub 9 pin female to female adapter
Db9 9pin Male To Male/female To Female/male To Female Mini Gender Changer Adapter Rs232 Serial Plug Com Connector - Pc Hardware Cables & Adapters - AliExpress
RS PRO D-sub Adapter Female 25 Way D-Sub to Female 25 Way D-Sub | RS
MODLINK MSDD GENDER CHANGER
Gender changer - Wikipedia
How to Make DB9 F/F serial RS232 mini gender changer? - Electrical Engineering Stack Exchange