Do you have a Serial Cable that needs converting to a Null cable? Instead of replacing your cable you can use this handy adapter to convert it to a female Null connection. Null cables only have 8 pins connected and so the 9th pin is not required.
Male to female mini null modem adaptor
Connections: 1+6-4, 2-3, 3-2, 4-1+6, 5-5, 7-8, 8-7