Based on comments here and some personal experience, I've been thinking about creating a X10 RF Link Command Translator.
Many of us have devices we would like to control with RF remotes, and other devices we would rather not have controlled accidentally. Sometimes these devices span several housecodes. While what I describe here is easily implemented in a high end controller, a PIC change to a RR501 could allow it to handle the translation.
Basically, the user would select any one housecode for the RF link. The modified RR501 would then translate RF housecode-unit pairs to any other housecode-unit X10 line commands. The RF link might also include a "security mode" where a 2 key input within a time window would be necessary to accept the command.
Any thoughts on how useful something like this would be?