Question: how to put nec phone on do not disturb?
Answer: While on-hook, press DND .
Select the DND type. Off = Turn DND off. Alternately dial 0 . External ( Ext ) = Block incoming outside calls. Alternately dial 1 . Intercom ( Icm ) = Block Intercom calls. ... 
Your telephone's display shows the type of DND you enabled. Your DND key is on.