1.5 Using a PDN/SDN Button1.5.1 Primary Directory Number (PDN)/Secondary DirectoryNumber (SDN) ExtensionPrimary Directory Number (PDN) buttons and Secondary Directory Number (SDN)buttons are useful when extension users will handle calls for other extensions. Forexample, a secretary or multiple secretaries can handle calls and check the call statusof a boss or multiple bosses. The functions of PDN and SDN buttons are as follows:PDN button: This button can be used to make and receive all calls (including bothoutside and intercom calls). Having multiple PDN buttons allows multiple calls to bequeued at the extension. 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 thefollowing operations:• 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.• 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.Flashing greenslowlyA call is on hold at the PDN extension(Regular Hold).A call answered with the SDN button ison hold (Regular Hold).Flashing greenmoderatelyA call is on hold temporarily or on ExclusiveCall Hold.A call answered with the SDN button ison hold temporarily or on Exclusive CallHold.Flashing greenrapidlyThe PDN extension is receiving an incomingcall.An SDN extension is receiving a HoldRecall or callback ringing from a callanswered with the SDN button.Red on A corresponding SDN extension is using theline.The corresponding PDN extension oranother corresponding SDN extensionis using the line.Flashing redslowlyA corresponding SDN extension is holding acall.Another corresponding SDN extension,or the PDN extension itself, is holding acall.User Manual 931.5.1 Primary Directory Number (PDN)/Secondary Directory Number (SDN) Extension