Avaya Partner 18D Phone - Black Provides feature buttons for 16 outside line, or programmable features such as Do Not Disturb and Auto Dial numbers Feature Button to simplify programming and access features Hold, Drop, Conference, Transfer, and two Intercom buttons Built-in speakerphone and microphone for totally hands-free calling Auxiliary Port allows quick connection of peripheral equipment, such as fax or answering machines Volume Control lets you increase or decrease the volume of the ringer, speaker, or handset