This stuff is pretty addicting. After 2 of my 400E cards died, I found 4 400H cards for cheap. So, now that I have 4 working cards I have to have the 4th card doing something. Since I have the Uverse line just for work, I ran it straight to the office and used the home wiring for my intercom. I plugged both sides of the ringdown in the house wiring with the red and green pair for the upstairs and downstairs and garage, and the black and yellow pair for the main floor. Now my wife can just pick up the phone and get a hold of the kids instead of yelling and them not hearing. I have both lines in the KSU as line 3 and 4. I had to add a ring amplifier to get all the phones on the first line to ring right though. I also have another 2565HK coming. I need to stop before I have 25 pair cable strung through the house.