Together with Partition, which component defines calling privileges?

• A. Device Mobility
• B. Line Group
• C. Route List
• D. Calling Search Space

Answer: (D)

In this dialing plan, access to numbers is controlled by partitions and the calling search space. Partitions group the dialable elements (like route patterns or translations), and the Calling Search Space (CSS) defines which partitions a device or user is allowed to reach when dialing. The combination determines what calling privileges you have: if the route you want to call lives in a partition not included in your CSS, the call is blocked; if it is included, the call is allowed.

For example, a CSS that includes only the Internal partition lets you call internal extensions, but blocks external numbers whose route patterns reside in another partition. If you expand the CSS to also include the External partition, external calls become possible. This is why the pair of CSS and Partition together defines dialing privileges.

The other options don’t define dialing privileges in that sense: Device Mobility relates to device registration behavior, Line Group to how lines are shared or assigned, and Route List to routing control—none of these directly establish which partitions you can reach when dialing.