diff --git a/src/bundle/Resources/richtext/schemas/docbook/docbook.iso.sch b/src/bundle/Resources/richtext/schemas/docbook/docbook.iso.sch
index c206b52c..a5ee69dd 100644
--- a/src/bundle/Resources/richtext/schemas/docbook/docbook.iso.sch
+++ b/src/bundle/Resources/richtext/schemas/docbook/docbook.iso.sch
@@ -253,20 +253,13 @@
     <s:let name="lowerCase" value="'abcdefghijklmnopqrstuvwxyz'"/>
     <s:rule context="db:link">
       <!-- Using translate() because we don't have XPath 2, so we can't use lower-case(). -->
-      <s:assert test="starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'http://') or
-                      starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'https://') or
+      <s:assert test="starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'http') or
                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'mailto:') or
-                      starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ezcontent://') or
-                      starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ezlocation://') or
-                      starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ezremote://') or
-                      starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ezurl://') or
+                      starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'tel:') or
+                      starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ez') or
                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), '/') or
                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), '#')"
-                mode="schematron-get-full-path-2">links must start with one of: http://, https://, mailto:, ezcontent://, ezlocation://, ezremote://, ezurl://, /, #</s:assert>
-      <s:assert test="not(contains(@*[name()='xlink:href'], '&lt;') or
-                          contains(@*[name()='xlink:href'], '&gt;') or
-                          contains(@*[name()='xlink:href'], '&quot;'))"
-                mode="schematron-get-full-path-2">using characters [&lt; &gt; &quot;] in links is not allowed</s:assert>
+                mode="schematron-get-full-path-2">links must start with one of: http://, https://, mailto:, tel:, ezcontent://, ezlocation://, ezremote://, ezurl://, /, #</s:assert>
     </s:rule>
   </s:pattern>
 </s:schema>
diff --git a/src/bundle/Resources/richtext/schemas/docbook/docbook.iso.sch.xsl b/src/bundle/Resources/richtext/schemas/docbook/docbook.iso.sch.xsl
index 6e4551bc..494d3a2b 100644
--- a/src/bundle/Resources/richtext/schemas/docbook/docbook.iso.sch.xsl
+++ b/src/bundle/Resources/richtext/schemas/docbook/docbook.iso.sch.xsl
@@ -79,7 +79,4 @@
 <axsl:template match="db:link" priority="1000" mode="M3"><svrl:fired-rule xmlns:svrl="http://purl.oclc.org/dsdl/svrl" context="db:link"/>
 
 		<!--ASSERT -->
-<axsl:choose><axsl:when test="starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'http://') or                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'https://') or                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'mailto:') or                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ezcontent://') or                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ezlocation://') or                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ezremote://') or                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ezurl://') or                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), '/') or                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), '#')"/><axsl:otherwise><svrl:failed-assert xmlns:svrl="http://purl.oclc.org/dsdl/svrl" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:schold="http://www.ascc.net/xml/schematron" test="starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'http://') or starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'https://') or starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'mailto:') or starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ezcontent://') or starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ezlocation://') or starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ezremote://') or starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ezurl://') or starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), '/') or starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), '#')"><axsl:attribute name="location"><axsl:apply-templates select="." mode="schematron-get-full-path-2"/></axsl:attribute><svrl:text>links must start with one of: http://, https://, mailto:, ezcontent://, ezlocation://, ezremote://, ezurl://, /, #</svrl:text></svrl:failed-assert></axsl:otherwise></axsl:choose>
-
-		<!--ASSERT -->
-<axsl:choose><axsl:when test="not(contains(@*[name()='xlink:href'], '&lt;') or                           contains(@*[name()='xlink:href'], '&gt;') or                           contains(@*[name()='xlink:href'], '&quot;'))"/><axsl:otherwise><svrl:failed-assert xmlns:svrl="http://purl.oclc.org/dsdl/svrl" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:schold="http://www.ascc.net/xml/schematron" test="not(contains(@*[name()='xlink:href'], '&lt;') or contains(@*[name()='xlink:href'], '&gt;') or contains(@*[name()='xlink:href'], '&quot;'))"><axsl:attribute name="location"><axsl:apply-templates select="." mode="schematron-get-full-path-2"/></axsl:attribute><svrl:text>using characters [&lt; &gt; "] in links is not allowed</svrl:text></svrl:failed-assert></axsl:otherwise></axsl:choose><axsl:apply-templates select="*|comment()|processing-instruction()" mode="M3"/></axsl:template><axsl:template match="text()" priority="-1" mode="M3"/><axsl:template match="@*|node()" priority="-2" mode="M3"><axsl:apply-templates select="*|comment()|processing-instruction()" mode="M3"/></axsl:template></axsl:stylesheet>
+<axsl:choose><axsl:when test="starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'http') or                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'mailto:') or                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'tel:') or                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ez') or                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), '/') or                       starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), '#')"/><axsl:otherwise><svrl:failed-assert xmlns:svrl="http://purl.oclc.org/dsdl/svrl" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:schold="http://www.ascc.net/xml/schematron" test="starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'http') or starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'mailto:') or starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'tel:') or starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), 'ez') or starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), '/') or starts-with(translate(@*[name()='xlink:href'], $upperCase, $lowerCase), '#')"><axsl:attribute name="location"><axsl:apply-templates select="." mode="schematron-get-full-path-2"/></axsl:attribute><svrl:text>links must start with one of: http://, https://, mailto:, tel:, ezcontent://, ezlocation://, ezremote://, ezurl://, /, #</svrl:text></svrl:failed-assert></axsl:otherwise></axsl:choose><axsl:apply-templates select="*|comment()|processing-instruction()" mode="M3"/></axsl:template><axsl:template match="text()" priority="-1" mode="M3"/><axsl:template match="@*|node()" priority="-2" mode="M3"><axsl:apply-templates select="*|comment()|processing-instruction()" mode="M3"/></axsl:template></axsl:stylesheet>
diff --git a/tests/lib/FieldType/RichTextTest.php b/tests/lib/FieldType/RichTextTest.php
index b37af517..e7eec106 100644
--- a/tests/lib/FieldType/RichTextTest.php
+++ b/tests/lib/FieldType/RichTextTest.php
@@ -229,7 +229,7 @@ public function providerForTestValidate()
                 [
                     new ValidationError(
                         "Validation of XML content failed:\n" .
-                        '/section/para/link: links must start with one of: http://, https://, mailto:, ezcontent://, ezlocation://, ezremote://, ezurl://, /, #',
+                        '/section/para/link: links must start with one of: http://, https://, mailto:, tel:, ezcontent://, ezlocation://, ezremote://, ezurl://, /, #',
                         null,
                         [],
                         'xml'
@@ -244,7 +244,7 @@ public function providerForTestValidate()
                 [
                     new ValidationError(
                         "Validation of XML content failed:\n" .
-                        '/section/para/link: links must start with one of: http://, https://, mailto:, ezcontent://, ezlocation://, ezremote://, ezurl://, /, #',
+                        '/section/para/link: links must start with one of: http://, https://, mailto:, tel:, ezcontent://, ezlocation://, ezremote://, ezurl://, /, #',
                         null,
                         [],
                         'xml'
@@ -257,13 +257,6 @@ public function providerForTestValidate()
   <para><link xlink:href="https://example.com/foo&lt;bar">link</link></para>
 </section>',
                 [
-                    new ValidationError(
-                        "Validation of XML content failed:\n" .
-                        '/section/para/link: using characters [< > "] in links is not allowed',
-                        null,
-                        [],
-                        'xml'
-                    ),
                 ],
             ],
             [
@@ -274,7 +267,7 @@ public function providerForTestValidate()
                 [
                     new ValidationError(
                         "Validation of XML content failed:\n" .
-                        '/section/para/link: links must start with one of: http://, https://, mailto:, ezcontent://, ezlocation://, ezremote://, ezurl://, /, #',
+                        '/section/para/link: links must start with one of: http://, https://, mailto:, tel:, ezcontent://, ezlocation://, ezremote://, ezurl://, /, #',
                         null,
                         [],
                         'xml'