atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Telecom Service & Providers MUX ring-trip problem

I just finished installing a new key system and discovered that when a ringing line (from a MUX across the street) is answered during a ring cycle the ring signal is plainly and sometimes painfully heard in the receiver when answering. If its just right it burns out the trunk interface. I lost 3 before I figured out what was happening. Using a butt-set its also there but tolerable. On the key sytem I can even answer a ringing line by pressing a line key and upon hearing the ring voltage hang-up and the line keeps ringing! Loop current is high at 80ma. I reduced it with some resistors to 30ma and it still occurs. Telco said ring voltage was 120v.
I tried another key system (same type) and blew a port on that one too. Aside from getting telco to fix this I can use a line sharing device to answer the line first (if it will survive!) or try another brand of key system. The customers old ksu didnt have this problem, of course! Ive been using an NEC DSX. Ive also posted this in the NEC forum. Any ideas? Thanks! Steve

Please do not post the same problem/question in multiple forums. It gets confusing. You already have answers in the NEC forum.