I have a multi site voip installation with a BCM 450 PBX. All site are reliated with T1 connections. My issue is that users from a remote office have a crosstalk issue.. I know that we can't have crosstalk on VOIP but it is the same symptom.
In fact when users from the remote office hook off to take a line they often hear someone else conversation for about 10 seconds. The other two people having this conversation can't hear the person who hook off.
It doesn't happen all time. It only happen on site with IP Phone.