I have two Pioneer CD-MR70 remotes and a Pioneer DEH-P680MP head unit. Pioneer has claimed we can use two remotes with a splitter and they will work (of course they said an MR70 would work with an MR80 and then changed their mind so we returned the 80 for a 70.) So far, they don't work two at the same time. If you only plug one in, it works fine. The buttons do not perform the correct functions when they are both hooked up. Anyone had any experience with this or have any suggestions? Thanks in advance.