Wondering if anyone has had this problem. Customer has a Nortel MIC's phone system with 6 lines and trunk and station expansion modules. When a call would come in on Line 1 it would ring twice and disconnect. When I would call in I would hear two rings, the disconnect and then you would hear a dial tone. I disconnected the line from the system and would ring the line at the Demarc only. No problems. I reconnected the line and the problem was there immediately. Next I swapped cards. No change. I moved the line to line 27 on the second card. Worked fine. Two weeks later line 3 did the same thing. Did all the tests and ended up moving to line 28. Worked fine. Eventually I replaced the line card. Moved lines back to Line 1 .3 on the new card. Worked fine for two weeks and then line 1 started doing it again. Had customer cal Telco and have them test the lines. They said all was OK. To make a long story short, I replaced the phone system, cards again, software, amp cables, 66 blocks, pairs to phone system from Telco. The last thing I did was measure the line voltage. All 6 lines are around 52.7 volts and 59 volts when ringing. What is the voltage range??? My guess is it is a Telco issue. Any HELPPP with this would be appreciated