You want to configure caller ID to display a user name instead of a dn for internal callers.
Which of the following line appearance fields should you modify in UCM?

A.
Display

B.
External Phone Number Mask

C.
Line Text Label

D.
Visual Message Waiting Indicator Policy

Explanation:
You should modify the Display (Internal Caller ID) line appearance field in the Cisco Unified Communications
Manager (UCM) administrative graphical user interface (GUI). Line appearance is the association between a
line and a device on a Voice over IP (VoIP) network. Because multiple lines can be associated with a single
device, you can configure multiple line appearances for a single IP phone. Line appearance configurations can
determine how a line that is associated with an IP phone displays information to an end user.
After you create a directory number (dn) in UCM and associate the line to a device, you will be able to edit line
appearance options that include display settings, such as internal caller ID, external caller ID, and the user
name or dn that is displayed beside a line button on an IP phone. When the Display (Internal Caller ID) field is
blank, the dn that is associated with the calling device is shown on the display of the called device. Otherwise,
the contents of the Display (Internal Caller ID) field are shown on the display of the called device.
You can configure the Display (Internal Caller ID) field with a name or a description of up to 30 characters in
length. If you configure the Display (Internal Caller ID) field, you should also configure the ASCII Display
(Internal Caller ID) field with similar information. The contents of the ASCII Display (Internal Caller ID) field are
displayed on called devices that do not support Unicode character sets. You cannot use non-ASCII characters
in the ASCII Display (Internal Caller ID) field.
You should not modify the Line Text Label field. The contents of the Line Text Label field are displayed beside
the associated line button of an IP phone. The field is typically configured with the name of the user that is
associated with the line. If the Line Text Label field is not configured, the dn that is associated with the line will
be displayed instead. For example, if user John Public has been assigned extension 4000, the dn 4000 will be
displayed beside the line button on the main screen of John Public’s IP phone unless you configure the Line
Text Label field. If you configure the Line Text Label field with the name John Public, that name will appear
beside the line button on the main screen of the IP phone. For shared workstations, you can configure the Line
Text Label field with the name of the department or office location that is associated with the IP phone. If you
configure the Line Text Label field, you should also configure the ASCII Line Text Label field with similar
information. The contents of the ASCII Line Text Label field are displayed on IP phones that do not support
Unicode character sets. You cannot use non-ASCII characters in the ASCII Line Text Label field.
You should not modify the External Phone Number Mask field. UCM transmits the contents of the External
Phone Number Mask field as caller ID information when an internal user places an outgoing call to an external
party. The information in the External Phone Number Mask field can be a string that consists of up to 24
numbers, the international escape character +, and X wildcards that represent the extension number.
The X wildcards should always be at the end of the string. For example, a user that has been assigned
extension number 4000 on the internal VoIP network might also be assigned a direct inward dial (DID) number
of (555) 5554000. Therefore, you could configure the External Phone Number Mask field with the string
555555XXXX. The number 5555554000 would then be displayed on the caller ID systems of any external
parties who are called by the user at extension 4000. If the user at extension 4000 was not assigned a DID
number, you could configure the External Phone Number Mask field with your company’s main public switchedtelephone network (PSTN) number instead.
You should not modify the Visual Message Waiting Indicator Policy field. The Visual Message Waiting Indicator
Policy field configures the behavior of the message waiting indicator (MWI) lamp and of the MWI line prompt on
an IP phone. For example, configuring the Visual Message Waiting Indicator Policy field to Light and Prompt
will configure the IP phone to turn on the MWI lamp that is located on the IP phone’s handset when a new voice
mail message arrives. In addition, the IP phone will display a new message prompt beside the associated line
button on the IP phone. However, configuring the Visual Message Waiting Indicator Policy field to Prompt Only
will display the new message prompt beside the line button but will not turn on the MWI lamp. You can
configure the Visual Message Waiting Indicator Policy field differently for each line that is associated with the IP
phone. For example, if the IP phone is configured with a shared line in addition to a primary line, you could
configure the Visual Message Waiting Indicator Policy field for the shared line to None so that the IP phone
never displays MWI information for the shared line.

Cisco: Directory Number Configuration: Directory Number Configuration Settings