Your remote is RF, but it sounds like your receiver will accept both RF and IR commands.

If the only setup code that works with the 2103 is 1313, then you won't be able to use advanced codes because they only work with setup codes starting with zero, with a few exceptions.

So, you won't be able to get an advanced code in, and you won't be able to learn anything on the 3100 from your Kenwood remote.

For some reason I can’t download the manual for your VR-509. Every time I try it locks up. I would have liked to be able to check this out in the manual but I will have to ask instead.

If your remote gives you direct access to the video inputs, the only thing I can suggest is to locate a store which has Kenwood receivers, find one with an IR remote, and learn the video input commands from it, if it has them, and see if they work.

Maybe edmund knows a way around this, which would be good because I am out of suggestions.