Let's all try to remember that "RJ" stands for "Registered Jack", not any kind of plug, cord or module. It is just an organized and uniform set of wiring schematics to make the same model of jacks (actually, they are technically connecting blocks) do many different things.
Oh, and the registered jack program came out decades before the IT industry was even weaned from the bottle.
There never was an RJ50. I rest my case, Your Honor.
