I have a 200L lw16 with comcast phone service 11 lines, all from arris box. been working fine for 5 years.

last week calls keep hitting the console, no one there. Staff answers the console and hears dial tone. I replaced the trunk card, the 25 pair and the cross connect from the arris box to the mitel, same issue. This is happening on two different trunk cards, on two different bays.

If I hook a 2500 phone to the trunk from the Arris box, no issue. Phone never rings.

Comcast says its the Mitel, I say it's Comcast.

I am at a loss!