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+++ b/Sphinx/source/faq/dicom.rst	Fri Apr 22 12:57:38 2016 +0200
@@ -0,0 +1,60 @@
+.. _dicom:
+
+Troubleshooting DICOM communications
+====================================
+
+In general, communication problems between two DICOM modalities over a
+computer network are related to the configuration of these
+modalities. As preliminary debugging actions, you should:
+
+* Make sure you use the `most recent version <http://www.orthanc-server.com/download.php>`_ of Orthanc.
+* Make sure the two computers can "ping" each other.
+* Turn off all the firewalls on the two computers (especially on Microsoft Windows).
+* Write down on a paper the following information about each modality:
+
+  * its IP address (avoid using symbolic names if possible to troubleshot any DNS problem),
+  * its TCP port for DICOM communications (for Orthanc, cf. the ``DicomPort`` option), and
+  * its AET (Application Entity Title - for Orthanc, cf. the ``DicomAet`` option).
+
+* Carefully re-read all your configuration files. As far as Orthanc is
+  concerned, the most important section is ``DicomModalities``: Make
+  sure its content matches what you wrote on the paper at the step
+  above.
+* In the ``DicomModalities`` configuration section of Orthanc, have a
+  look at the fourth parameter that can activate some patches for
+  specific vendors.
+* Have a look at the following options of Orthanc to enable the more fault-tolerant DICOM support:
+
+  * ``DicomServerEnabled`` must be set to ``true``.
+  * ``DicomCheckCalledAet`` should be set to ``false``.
+  * All the transfer syntaxes should be set to ``true`` (see the
+    options with a ``TransferSyntaxAccepted`` suffix).
+  * Temporarily disable any Lua script and any plugin, i.e. set the
+    options ``LuaScripts`` and ``Plugins`` both to the empty list.
+  * ``DicomAssociationCloseDelay`` should be set to ``0``.
+
+* Restart Orthanc with the ``--verbose`` option at command line, and
+  carefully inspect the log. This might provide immediate debugging
+  information.
+* Issue a :ref:`DICOM C-Echo <dicom-echo>` from each modality to make
+  sure the DICOM protocol is properly configured (sending a C-Echo
+  from Orthanc Explorer is possible starting with Orthanc 0.9.3, in
+  the "Query/Retrieve" page).
+* If the two modalities succeed with C-Echo, but query/retrieve does not
+  succeed, please carefully read the :ref:`dicom-move` section.
+
+As a last resort, please contact the `mailing list
+<https://groups.google.com/forum/#!forum/orthanc-users>`_ by sending a
+detailed description of your problem, notably:
+
+* What fails: The sending of a file (aka. C-Store SCU), the searching
+  of a patient/study (aka. C-Find SCU), or the retrieve of a file
+  (aka. C-Move SCU)? Is Orthanc acting as a client or as a server?
+* Describe your network topology, as written above on your paper (IP
+  address, port number, and AET for both modalities).
+* Specify the operating system, the vendor, the DICOM software, and
+  the version of each modality.
+* Attach sample DICOM files, possibly anonymized.
+* Attach the log of the two modalities. The log must be generated with
+  the ``--trace`` command-line option as far as Orthanc is concerned.
+* Attach any screenshot that is useful to understand the problem.