An engineer is configuring a user to have Cisco Extension Mobility. Where is the line configured?

The Device Profile in CUCM is the core component of Extension Mobility - it stores the user's directory numbers (lines), speed dials, services, and other phone settings. When a user authenticates to a phone via Extension Mobility, the Device Profile is dynamically loaded onto that physical device, replacing its default configuration. Lines must be assigned within the Device Profile, not the physical phone, so the configuration follows the user.

The CAPF Profile is used to provision and manage LSC certificates on endpoints for authentication security and is unrelated to line configuration.

The Primary Extension field on a user record identifies the user's main DN but does not configure the line settings used during an Extension Mobility session.

User Configuration in CUCM manages user attributes and associations but does not directly define the line settings presented during an Extension Mobility login.