We currently have a Cisco 2620 that connects our main office with a branch office out of state with voice and data over a T1 line. We are about to change T1 providers and they want to put a T1 mux in front of everything to split the voice and data. I need to know if this is a good idea and what the various trade-offs would be. They also talked as if they only needed to put this in the main office, so I need to know if this is true and how it would effect the configuration at the branch office as well.