--- a/ttml10/spec/ttaf1-dfxp.xml	Wed Apr 25 22:23:33 2012 -0600
+++ b/ttml10/spec/ttaf1-dfxp.xml	Thu Jun 14 07:42:24 2012 -0600
@@ -588,6 +588,14 @@
 </def>
 </gitem>
 <gitem>
+<label>Document Interchange Context</label>
+<def>
+<p>The implied context or environment external to a <emph>Content Processor</emph> in
+which document interchange occurs, and in which out-of-band protocols or procedures
+may define certain behavioral defaults, such as an implied <emph>Content Profile</emph>.</p>
+</def>
+</gitem>
+<gitem>
 <label>Element Information Item</label>
 <def>
 <p>Each element appearing in an XML document corresponds with an element information
@@ -1162,10 +1170,11 @@
 <loc href="#parameter-attribute-profile"><att>ttp:profile</att></loc>
 attribute nor
 <loc href="#parameter-vocabulary-profile"><el>ttp:profile</el></loc>
-element is present in a TTML document instance, and if the document
-interchange context does not specify a profile,
-then the DFXP Transformation
-profile applies.</p>
+element is present in a TTML document instance, and if the Document
+Interchange Context does not make an implicit or explicit
+reference to a pre-defined Content Profile, and does not specify a Profile Definition
+Document or another equivalent set of feature designations,
+then the DFXP Transformation profile applies.</p>
 <note role="elaboration">
 <p>It is intended that the <att>ttp:profile</att> attribute be used when
 the author wishes to reference one of the standard, predefined profiles of