Samsung SAM4s ER-5240M, Can I program any thing while the "Program Mode"?

You may be correct on the coded sign-on. Personally, I would recommend that you MAC (Memory All Clear) the register to return it to an out-of-the-box state and then reprogram it. This will ensure you don't inherit any undesirable option (or other) settings from the previous owner. If you have the manual, the procedure is on pg. 78 and you will need a Service (with a 'C' stamped on it) key to perform this procedure. If you don't have a Service key, you'll have to take the register to a dealer and have it done.

Steve
December 2009