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!!!

Add your own secondary line protectors.

Duh, losing a line? Are you swapping out a 4CO DS card every month? Are you rebooting to make it come back? Is it dropping out of your line assingments? Information is missing here.

The more specific you can be about what you have done or tried and didn't work plus what equipment revision you have, the easier it is to help you.

What mics software revision? DS cards or the old non-DS cards? If it doesn't say DS, it is an old card unless it is a C1 caller ID card.