Nortel phone systems enable you to determine who calls your line and when you can be called. Incoming phone calls that are not priority calls can be blocked temporarily using the Do Not Disturb feature. The Do Not Disturb feature can also be used to temporarily block all calls while you're on the phone. The Do Not Disturb Feature is activated by a simple code input into the telephone. The Priority call feature must be activated by the caller in advance of calling the line in Do Not Disturb mode.
Press the "Feature" button. The button says "Feature" or resembles a circular globe with a drawn orbit around the globe.
Press the "8" button then the "5" button. No calls will get through unless the caller makes his call a priority by pressing his own "Feature" button followed by the "6" button and "9" button. No calls will be able to get through when you make a call while utilizing the Do Not Disturb feature.
Press the "Feature" button followed by "#", "8", and "5" to turn off the Do Not Disturb feature.