Avaya Partner MLS 18 Phone (White/Refurbished)Avaya Partner MLS 18 Telephone. More Information 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 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,