Primary [DN] Buttons

Primary Directory Number buttons [PDNs] are needed to make calls and receive calls. It is a

telephone’s main extension number. Each telephone is assigned only one [PDN] and that telephone is designated as the owner of the [PDN]. This [PDN] button can be made to appear multiple times on other telephones (see Secondary [DN] Buttons). Features, Class of Service, etc., are associated only with the station assigned as the owner of the [PDN]. [PDNs] that appear on telephones other than the owner telephone are referred to as Secondary DNs [SDNs].