One of my wife's friends has a KSU 550 and punch-down block in the basement. I am trying to convince her to let me remove the dinosaur from her house (I have a plan to install it in a Don Draper-style office in the house). If I succeed, I will need to know how to remove it and to figure out if the phone system is still going through it. I think it is using some of the 25 pair to connect to sets throughout the house, without using the KSU itself.