I have this mics system,and it never fails about once a month,we lose a line on one of the trunk cartridges,and its always a different line or different cartridge,we have 12 c.o lines all together,we do have ultralinx surge protection on the co lines,we are getting a good surge from somewhere. c.o says its not them,and im not saying it is them.we are now in the process of rerouting all co lines inside the clients building to make sure nothing is interfering.any comments are welcomed,help!!!