Hello, and thank you for using the ADTRAN Support Forums.
Chances are that if there are no cables connected to the module then it is not being used, but knowing what type of module it is will help to clarify this.
If the module is not currently in use, then you can swap the two modules.
the default LOGIN for the ATLAS is "password" and the default IP address is 10.0.0.1 with a subnet mask of 255.255.255.0. If the LOGIN has been changed or the IP address is unknown, then you will need a serial connection to the front CRAFT port or the ADMIN port on the back of the controller module (https://supportforums.adtran.com/docs/DOC-3471). With a serial connection to the ATLAS there is a challenge/response procedure that restores the default login, but this is best done over the phone with support, as the response must be given during the same session as the challenge, or the process must be repeated.