Welcome to the forum, Gina. Good question. And I have an answer.
My old Phillips Universal does work with an RCA box. I used the code search method and I hit a BINGO on the 8th ch+ button. This remote is a few years old. I bought it at Wal-Mart long time ago for like 4 bucks. My sis (the yard sale queen) says she has seen converter boxes for about 10 bucks at yard sales.