The number 600 sticks in my head and the manual is very specific about the fact that the TOTAL of all runs is 600 feet. At the very best, you must hang all 3 phones at the end of the run and not try to run 3 separate cables/pairs for each phone, no matter what ports you hang them on. In addition, you may have to hang the 4th "endpoint device" on the cable to balance out the signals.


Carl