I know this question has been raised and I have spent a great deal of time reviewing the posts to see if anyone has solutions that I have not already checked. We are a Nortel Partner, now Avaya and develop third party software as PC Based Attendant Consoles. With our software we provide a logging feature that captures all messages between the PC, the M2250, or PCCIU, and the PBX. In our logging messages, I do get a set Lamp "BUSY" which we react to. I am extremely familiar with how the Busy/ Night works and how the handsets and headsets may play a role in the activation. From a PBX programming perspective, would there be anything that might do this, e.g. AFNT/ AFBT or others.