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!

Just a thought....Take a telephone buttset and connect to one of the lines....put the buttset on monitor and listen while the console answers the call...when the console does answer and you hear dialtone...listen on the buttset/put it on talk and see if you get the caller

You can also put a meter on the line and see if the trunk is a little "HOT" it may not be enough to ring a 2500 set but the system could see the hot line and ring the answer point. I agree with you its probably comcast

In the trunk descriptor, make sure "Ringing Expected" is set to YES.
That tells the Mitel to only react to 90V ringing for incoming calls. Otherwise, any change in line condition, and the Mitel assumes it's an incoming call.

ringing expected was set to NO. I changed it and we'll see what happens.

otherwise my next step was a meter

thanks for the tip!