In some scenarios you don't want the editor to be able to use a fully fledged CMS_INPUT_DOM component. There are switches to disable bold or italic for example. A less know option is to disable links, which can be done by providing an empty LINKEDITOR param:
<CMS_INPUT_DOM name="pt_text">
<LANGINFOS>
<LANGINFO lang="*" label="Text"/>
</LANGINFOS>
<LINKEDITORS>
<LINKEDITOR name=""/>
</LINKEDITORS>
</CMS_INPUT_DOM>
Here's an example of a stripped down CMS_INPUT_DOM component, which doesn't allow any kind of formatting. You might want to use this if the editor should enter an (unformatted) teaser.
<CMS_INPUT_DOM name="pt_text" bold="no" italic="no">
<LANGINFOS>
<LANGINFO lang="*" label="Text"/>
</LANGINFOS>
<FORMATS>
<TEMPLATE name="p"/>
</FORMATS>
<LINKEDITORS>
<LINKEDITOR name=""/>
</LINKEDITORS>
</CMS_INPUT_DOM>