13.1.7 PDN (Primary Directory Number)/SDN (Secondary DirectoryNumber) Extension
Description
Primary Directory Number (PDN) buttons and Secondary Directory Number (SDN) buttons are ideal for use
between bosses and secretaries. When a call (intercom or CO) arrives at a PDN button on the boss’s extension,
the call will ring and the LED of the SDN button will flash at the secretary’s extension as well, indicating that
an incoming call is arriving at the boss’s extension. In addition, caller information (e.g., Caller ID) of the incoming
call will appear on the secretary’s extension. The secretary can answer the call for the boss by simply pressing
the SDN button. Delayed ringing can be set for a PDN or SDN button.
A secretary can hold a call answered on the SDN button, and the boss can retrieve the held call simply by
pressing the PDN button, like when answering a call with an S-CO button. In addition, a secretary can transfer
calls from an SDN button or other button (e.g., S-CO button) to the boss’s extension with a simple operation,
like when using a DSS button.
An extension can have several SDN buttons, each registered to a different boss’s extension. However, only
one SDN button can be registered for a single boss at each extension. An extension can have up to eight PDN
buttons. PDN buttons can simplify the use of an extension because both intercom and CO line calls can be
made and received at a PDN button.
This feature is only available for the KX-TDA100, KX-TDA200, and KX-TDA600.

Making Calls with an SDN Button

When Standard SDN Key mode is assigned to an SDN extension (secretary) through COS programming, SDN
extensions (secretaries) can make calls for PDN extensions (bosses) on the SDN button. For example, a boss
can ask a secretary to make a call and put the call on hold, after which, the boss can retrieve the held call.
Through COS programming, it is possible to allow an SDN extension to make calls using the COS of the PDN
extension. All other settings that are available when using the Walking COS feature are also applied (®
20.1.1 Walking COS).
SDN Direct Dial
An SDN extension can call a PDN extension or transfer a call to a PDN extension using an SDN button.
In this case:
–Only the PDN extension rings (i.e., other SDN extensions do not ring).
–The delayed ringing and DND settings of the PDN extension are ignored.
Depending on the mode selected through COS programming, SDN Direct Dial is performed in one of two ways,
as follows:
–Enhanced DSS Key mode: pressing the SDN button once.
–Standard SDN Key mode: pressing the SDN button twice (a dial tone is heard the first time the SDN button
is pressed).
Calls answered using the SDN button can be transferred to the PDN extension by simply pressing the SDN
button once, regardless of the mode.

LED Indication

The LED patterns and the corresponding status of PDN and SDN buttons are as follows:
Light Pattern PDN Button Status SDN Button Status
Off This extension is idle. The corresponding PDN extension is idle.
Green on The extension is on a call using the PDN
button.
The extension is on a call using the SDN
button.
Slow green
flashing
A call is on hold using the PDN button. A call is on hold using the SDN button.
Document Version 2008-11 Feature Manual 213
13.1.7 PDN (Primary Directory Number)/SDN (Secondary Directory Number) Extension