Panasonic KX-NCP500 Operating Manual page 23

Button
Cleaned-up
Primary Directory Number
(PDN)
Secondary Directory Number
(SDN)
Document Version 2013-05
Used to switch the room status of extensions between Ready and Not
Ready.
Used to make and receive both outside and intercom calls.
Used to show the current status of another extension, call the extension,
and pick up or transfer calls to it.
1.1.1 Before Operating the Telephones
Feature
Operating Manual 23