I am wanting to update this old Tone Remote Base Unit to a new model. After opening up the old unit it looks like it is just a two wire system. Does anyone see any reason why I shouldn't be able to exchange this units? Any advice or suggestions when doing something like this? Doesn't appear to be that difficult I just ran out of time today and will not get a chance to work on this project for a few more days so I figured I would check on here for input. Thanks!!