A customer of ours has a BCM 400 they also have a separate Aiphone with 3 door boxes and strikes there are 5 Aiphone LEF-3L controllers located around the building. They want to add an additional door box and strike but the AIphone LEF-3l will only handle 3 doors. Instead of upgrading the LEF-3L's to LEF-5L's (control of up to 5 doors) and having to pull additional pairs between the LEF units I suggested going with Nortel Door boxes and controllers which they seem to like. I have just noticed the LEF-3L's have been modified with an on off switch that they use. (4 of the 5 LEF units are in offices). Since the user can't change door phone ring assignments at will I am wondering if a DND button would stop door phone ringing on a BCM ?
conversely has anyone ever integrated the Aiphone system through co's to a BCM.

DND will work if that CO programmed to ring on that one Exten. You can take that line assignment off of those extens. which they don't want to ring.