It is easy to find this kind of reference when searching for IR protocols and codes for specific equipment. The actual IR transmission contains far more data than these small codes can hold.
What exactly do these codes represent?
How can four digits represent all the commands a device can receive?
Are these "codes" references to some standard protocol? How do the universal remote knows the protocol and all the codes the product understands from this small configuration code?
I would love to understand more about this technology. For me it seems that every remote is different, and you would have to reverse engineer every message to identify which bit/byte does what.