I just sold the remote control for the Lenoxx Sound HT-500 home cinema DVD player by Regent and now the buyer is asking me if i know how to program the remote. The buyer believes they have a 4 digit code but doesn't know what to do in order to pair it with the player?

I have no clue myself, and don't recall having to do this when we last used the player in the mid 2000s. I hope someone can help :/