I support a Partner System R5 with Transtalks. The Transtalks have been nothing but problems and the owners want them replaced. I thought about the 3910 but the owner wants to be able to handle 4 lines at minimum. So the 3910 will not suffice. Can anyone recommend something that can handle 4 lines and can work behind this Partner?

If not the owner is willing to rip it all out for something that will give them what they need. This is a residence for very wealthy owners and money isn't really an issue. I'm trying to avoid having to have wireless access pts. installed all over the house.