Our CIX 40 phone system has had a strange intermittent problem where the extensions with the DND set will occasionally decide to start ringing on incoming calls on the CO lines. It has happened on both the office DKT-5022s and remote IPT-5022s, but seems significantly more troublesome on the IPTs. The ringing will stop if you un-set and re-set DND, but it will come back over time. Today I was fooling around with the class of service settings with eManager. Primarily I was adjusting DND override and Executive override there. Now my own IPT extension's DND barely works. I have to reset it every few calls to silence the ring. It may be of some significance that the extensions all have a second programmable button that flashes along with the line button. The auto-attendant is set to answer after caller ID info is sent on incoming calls, so the second light helps us ensure that we aren't picking up calls before the standard greeting is played. Thanks for any ideas.