The RS232 Null-Modem Adapter changes a DSUB9 female port into a DSUB9 male connector. The Adapter is not just a Gender Changer. RS232 requires different signal positions for male and female connectors, so this adapter exchanges those positions. Don't use it for RS422/485.
Null-Modem 9PM-9PM is a spare-part for NetCom Serial Device Servers.