intertone gap maximum

Fix for Issue #1289

webrtc.html

@@ -9370,8 +9370,8 @@ <h2>Methods</h2>
               cannot be more than 6000 ms or less than 40 ms. The default
               duration is 100 ms for each tone.</p>
               <p>The interToneGap parameter indicates the gap between tones in
-              ms. The user agent clamps it to at least 30 ms. The default value
-              is 70 ms.</p>
+              ms. The user agent clamps it to at least 30 ms and at most
+              6000 ms. The default value is 70 ms.</p>
               <p>The browser MAY increase the duration and interToneGap times
               to cause the times that DTMF start and stop to align with the
               boundaries of RTP packets but it MUST not increase either of them
@@ -9406,6 +9406,9 @@ <h2>Methods</h2>
                 <li>If the value of the <code><a data-for=
                 "RTCDTMFSender">interToneGap</a></code> parameter is less than
                 30, set it to 30.</li>
+                <li>If the value of the <code><a data-for=
+                "RTCDTMFSender">interToneGap</a></code> parameter is more than
+                6000, set it to 6000.</li>
                 <li>If <code><a data-for="RTCDTMFSender">toneBuffer</a></code>
                 is an empty string, abort these steps.</li>
                 <li>If a <em>Playout task</em> is scheduled to be run; abort