Merged revisions 310888 via svnmerge from

Merged revisions 310888 via svnmerge from
https://origsvn.digium.com/svn/asterisk/branches/1.4

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  r310888 | twilson | 2011-03-16 11:58:42 -0500 (Wed, 16 Mar 2011) | 29 lines

  Don't delay DTMF in core bridge while listening for DTMF features

  This patch is mostly the work of Olle Johansson. I did some cleanup and
  added the silence generating code if transmit_silence is set.

  When a channel listens for DTMF in the core bridge, the outbound DTMF is not
  sent until we have received DTMF_END. For a long DTMF, this is a disaster. We
  send 4 seconds of DTMF to Asterisk, which sends no audio for those 4 seconds.
  Some products see this delay and the time skew on RTP packets that results and
  start ignoring the audio that is sent afterward.

  With this change, the DTMF_BEGIN frame is inspected and checked. If it matches
  a feature code, we wait for DTMF_END and activate the feature as before. If
  transmit_silence=yes in asterisk.conf, silence is sent if we paritally match a
  multi-digit feature. If it doesn't match a feature, the frame is forwarded
  along with the DTMF_END without delay. By doing it this way, DTMF is not delayed.

  (closes issue #15642)
  Reported by: jasonshugart
  Patches:
        issue_15652_dtmf_ast-1.4.patch.txt uploaded by twilson (license 396)
  Tested by: globalnetinc, jde

  (closes issue #16625)
  Reported by: sharvanek

  Review: https://reviewboard.asterisk.org/r/1092/
  Review: https://reviewboard.asterisk.org/r/1125/
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git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.6.2@310889 65c4cc65-6c06-0410-ace0-fbb531ad65f3