How to use XR11-RF remote to control volume on the HDMI cable coming out of a Contour mini-box?

No help. The steps don't track with the XR11-RF controller.

I think what you need is the code to disable volume lock, which bonds the volume buttons to the TV function. The old code was 993. I found this, which mentions a way to change the bond to another device, but I don't think there is a way for it to default to cable function. Sorry. Maybe someone else will have a better idea. Good luck!

I don't think the Cox Contour mini-box is capable of volume control on its own.

I'm trying to get this to work with a very weird setup.
Cox doesn't play well with weird setups.
I'll have to stick to turning the volume control knob manually on my Logitech speakers.
It's like the 50's again!

You could upgrade to a remote controlled speaker system. Sound bars are pretty cheap if you have room on the desk. Anything that uses IR would probably be compatible with the Cox remote. I know you probably didn't want to throw money at the problem, but something to consider.