Gender Changer or Null Modem - What's the Difference

[nasttcar]

I have an application that calls for me to connect two serial cables, each with 9 pin female ends. The instructions say to use a 9 pin, male/male, null modem.

At my local Fry's they had a 9pin, male/male, gender changer.

What's the difference?

I will presume there is a difference because I could not get communication established.

Where do I find the type of null modem I need?

 

[Dowfen]

A null modem cable switches the "from" and "to" signals and ties the grounds together. A regular serial cable with a gender bender on the end won't give you that.

Eric