We have 3CX v. 15.5 and Yealink T-48G phones. The Yealink phones have a DND button, and when pressed, the DND icon shows on the phone and the presence indicators show a red square for Do Not Disturb. However, if you are on DND, someone can still intercom to your phone and it will come through instead of returning a busy indicator. I cannot figure out how to get it to block intercom calls as well. The 3CX system has dial codes that can be used. If we use those, the phones do not display the DND icon, but the presence indicator goes to a red square with a white line through it. This mode does NOT allow intercom calls to come through, however, it's not as convenient for people to use and they forget to take it off because the phone doesn't show any icon indicating they're in DND mode. Without having to use both methods every time someone goes to lunch, etc., does anyone know how to get the built in Yealink DND to block intercom calls, too?