Off-hook. On-hook.DPTEnter 1 to ringor 0 not to ring.RingNo ring10OREnter 39.3 9 C.Tone• Even if "No ring" is selected, calls can be made and answered on the single line telephoneby lifting the handset.• If you go off-hook while your paralleled telephone is in use, the call will switch over toyou.1.3.49 PDN (Primary Directory Number)/SDN (Secondary DirectoryNumber) ExtensionPrimary Directory Number (PDN) buttons and Secondary Directory Number (SDN) buttonsare useful when extension users will handle calls for other extensions. For example, asecretary or multiple secretaries can handle calls and check the call status of a boss or multiplebosses. The functions of PDN and SDN buttons are as follows:PDN button: This button can be used to make and receive all calls (including both outsideand intercom calls). Having multiple PDN buttons allows multiple calls to be queued at theextension. Extensions that have a PDN button are called PDN extensions.SDN button: The light of an SDN button displays the current call status of the registeredextension, similar to a DSS button. In addition, this button can be used to perform the followingoperations:• call the PDN extension ( SDN Direct Dial)• answer calls ringing at the PDN extension• hold calls and retrieve calls held by the PDN extension ( Call Hold and Call HoldRetrieve)• transfer calls to the PDN extension ( Call Transfer Using SDN Button)Extensions that have an SDN button are called SDN extensions.• The extension that is registered as the destination of an SDN button must have at least onePDN button.• One extension can have up to 8 PDN buttons.• An extension can have only one SDN button for each PDN extension.• A PDN extension can only receive OHCA or Whisper OHCA from the corresponding SDNextension. When a call is made from another extension, a PDN extension will receive a callwaiting tone.• The button light of each PDN/SDN button shows the current status as follows:Light Pattern PDN Button Status SDN Button StatusOff The PDN extension is idle.Green on The extension is on a call using the PDNbutton.The extension is on a call using an SDNbutton.104 Operating Manual Document Version 2009-111.3.49 PDN (Primary Directory Number)/SDN (Secondary Directory Number) Extension