Hi,
Activitypointer contains only the fields that are common to all activity types.
To get the phonecall field you need to link activitypointer with other entities (phonecall/email) and then
you can get the attributes of related entity.
write your query something like below-
<fetch mapping="logical" count="50" version="1.0">
<entity name="activitypointer">
<attribute name="subject" />
<link-entity name="phonecall" from="activityid" to="activityid" alias="phcall" link-type="outer">
<attribute name="phonenumber" />
</link-entity>
</entity>
</fetch>