Addressing
Click on the red underlined text to get to the source
... telephone number [E164], including any sub-addressing portion. The
normal search will be for this attribute.
...
... telephoneNumber in [LDAP] in its
support for sub-addressing information and its use as a voice
messaging address. In most cases, these values will be the same.
...
... queried telephone number. This information may be used to provide a
post-dial sub-addressing menu to the sender.
...