I was thinking about buying the HTM MX500.
I bought the Promedia DD 5.1. It's very inexpensive and does all I need.
I saw a lot about discrete codes, which I know only they are distinguised codes on buttons that cycle. The DD5.1 has an input button which cycles through all the inputs.
First how do I tell if the DD5.1 has discrete codes for each input.
Second how do I extract each code, or get the discrete code, in order to program a remote. If I understand it correctly I would need to get something like Mike C & Dave are inventing to be able to put the discrete for each input into a button and then send it back to the remote.

I'm new to this stuff, but want to get a good universal remote. I want as little complication as possible.

Thanks,
Doug