diff --git a/src/gui/ctrl/bus-controller.cpp b/src/gui/ctrl/bus-controller.cpp
index 66b362dde..9edb4bdaa 100644
--- a/src/gui/ctrl/bus-controller.cpp
+++ b/src/gui/ctrl/bus-controller.cpp
@@ -43,6 +43,7 @@
 //#include "include/logging.h"
 #include "gui/ctrl/bus-term.hpp"
 #include "gui/ctrl/bus-controller.hpp"
+#include "gui/ctrl/nexus.hpp"
 
 //#include <boost/noncopyable.hpp>
 #include <string>
diff --git a/src/gui/ctrl/nexus.hpp b/src/gui/ctrl/nexus.hpp
new file mode 100644
index 000000000..a43c8cb39
--- /dev/null
+++ b/src/gui/ctrl/nexus.hpp
@@ -0,0 +1,115 @@
+/*
+  test/NEXUS.hpp  -  fake user interface backbone for test support
+
+  Copyright (C)         Lumiera.org
+    2015,               Hermann Vosseler <Ichthyostega@web.de>
+
+  This program is free software; you can redistribute it and/or
+  modify it under the terms of the GNU General Public License as
+  published by the Free Software Foundation; either version 2 of
+  the License, or (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+
+/** @file test/nexus.hpp
+ ** Core hub and routing table of the UI-Bus.
+ ** Any relevant element within the Lumiera GTK UI is connected to the [UI-Bus][ui-bus.hpp]
+ ** through some [bus terminal][bus-term.hpp]. Actually, there is one special BustTerm
+ ** implementation, which acts as router and messaging hub.
+ ** 
+ ** @todo initial draft and WIP-WIP-WIP as of 11/2015
+ ** 
+ ** @see abstract-tangible-test.cpp
+ ** 
+ */
+
+
+#ifndef GUI_CTRL_NEXUS_H
+#define GUI_CTRL_NEXUS_H
+
+
+#include "lib/error.hpp"
+//#include "lib/idi/entry-id.hpp"
+#include "gui/ctrl/bus-term.hpp"
+//#include "lib/util.hpp"
+//#include "gui/model/tangible.hpp"
+//#include "lib/diff/record.hpp"
+#include "lib/idi/entry-id.hpp"
+
+#include <boost/noncopyable.hpp>
+//#include <string>
+
+
+namespace gui {
+namespace ctrl{
+  
+//  using lib::HashVal;
+//  using util::isnil;
+//  using lib::idi::EntryID;
+//  using lib::diff::Record;
+//  using std::string;
+  
+  
+  /**
+   * Central hub of the UI-Bus.
+   * This special implementation of the [BusTerm] interface maintains
+   * a routing table and manages the connections to individual UI-Elements.
+   * 
+   * @todo write type comment
+   */
+  class Nexus
+    : public BusTerm
+    , boost::noncopyable
+    {
+      using ID = lib::idi::BareEntryID const&;
+      using Tangible = gui::model::Tangible const&;
+      
+      
+      virtual void
+      note (ID subject, GenNode const& mark)  override
+        {
+          UNIMPLEMENTED ("forward note messages to the presentation state manager");
+        }
+      
+      
+      virtual void
+      mark (ID subject, GenNode const& mark)  override
+        {
+          UNIMPLEMENTED ("route mark messages down to the individual Tangible");
+        }
+      
+      
+      virtual BusTerm&
+      routeAdd(Tangible newNode)  override
+        {
+          UNIMPLEMENTED ("add a new down-link connection to the routing table");
+        }
+      
+      
+      virtual void
+      routeDetach(ID node)  noexcept override
+        {
+          UNIMPLEMENTED ("deactivate and remove a down-link route");
+        }
+      
+    public:
+      explicit
+      Nexus (BusTerm& coreService)
+        : BusTerm(lib::idi::EntryID<Nexus>(), coreService)
+      { }
+    };
+  
+  
+  
+}} // namespace gui::ctrl
+#endif /*GUI_CTRL_NEXUS_H*/
diff --git a/tests/gui/test/nexus.cpp b/tests/gui/test/nexus.cpp
index a5e369cc6..50ecd4d4b 100644
--- a/tests/gui/test/nexus.cpp
+++ b/tests/gui/test/nexus.cpp
@@ -37,6 +37,8 @@
 //#include "lib/symbol.hpp"
 //#include "include/logging.h"
 #include "test/nexus.hpp"
+#include "gui/ctrl/nexus.hpp"
+#include "lib/depend.hpp"
 
 //#include <boost/noncopyable.hpp>
 //#include <string>
@@ -53,6 +55,8 @@ namespace test{
   
   namespace { // internal details
     
+    lib::Depend<gui::ctrl::Nexus> testNexus;
+    
   } // internal details
   
   
@@ -69,7 +73,7 @@ namespace test{
   ctrl::BusTerm&
   Nexus::testUI()
   {
-    UNIMPLEMENTED("test nexus");
+    return testNexus();
   }
 
 }} // namespace gui::test
diff --git a/tests/gui/test/nexus.hpp b/tests/gui/test/nexus.hpp
index 70dcb6cba..87fa9179e 100644
--- a/tests/gui/test/nexus.hpp
+++ b/tests/gui/test/nexus.hpp
@@ -28,7 +28,10 @@
  ** backbone to run any test probes against. The test::Nexus allows to [hook up][::testUI]
  ** a generic interface element, to participate in a simulated interface interaction.
  ** 
- ** @todo initial draft and WIP-WIP-WIP as of 11/2015
+ ** This class test::Nexus acts as front-end for unit tests, while the actual implementation
+ ** of a test rigged mock interface backbone remains an implementation detail.
+ ** 
+ ** @todo initial draft and WIP-WIP-WIP as of 12/2015
  ** 
  ** @see abstract-tangible-test.cpp
  **