This DSS Console is often used for additional buttons on a receptionist phone so they can take a quick glance and see whether a user is on the phone or available for a call
The Programmable Buttons can be used for BLF/DSS (Busy Lamp Field/ Direct Station Select Buttons), Line Appearances, Ring Groups, Voice Mail Transfer, Door Opener Control
The KXDT390 connects to the system through a Digital Extension Port and requires its own port in addition to the telephone that it is connected to, for a total of 2 ports.