diff --git a/tools/cooja/java/se/sics/cooja/contikimote/interfaces/ContikiRadio.java b/tools/cooja/java/se/sics/cooja/contikimote/interfaces/ContikiRadio.java
index a697e4fa2..470fdadd1 100644
--- a/tools/cooja/java/se/sics/cooja/contikimote/interfaces/ContikiRadio.java
+++ b/tools/cooja/java/se/sics/cooja/contikimote/interfaces/ContikiRadio.java
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: ContikiRadio.java,v 1.26 2009/02/25 14:46:22 fros4943 Exp $
+ * $Id: ContikiRadio.java,v 1.27 2009/04/16 14:26:35 fros4943 Exp $
  */
 
 package se.sics.cooja.contikimote.interfaces;
@@ -176,7 +176,7 @@ public class ContikiRadio extends Radio implements ContikiMoteInterface, PolledA
   }
 
   /* General radio support */
-  public boolean isOn() {
+  public boolean isReceiverOn() {
     return radioOn;
   }
 
diff --git a/tools/cooja/java/se/sics/cooja/interfaces/ApplicationRadio.java b/tools/cooja/java/se/sics/cooja/interfaces/ApplicationRadio.java
index ab550ac3d..472677e86 100644
--- a/tools/cooja/java/se/sics/cooja/interfaces/ApplicationRadio.java
+++ b/tools/cooja/java/se/sics/cooja/interfaces/ApplicationRadio.java
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: ApplicationRadio.java,v 1.8 2009/03/09 14:08:54 fros4943 Exp $
+ * $Id: ApplicationRadio.java,v 1.9 2009/04/16 14:26:36 fros4943 Exp $
  */
 
 package se.sics.cooja.interfaces;
@@ -320,4 +320,8 @@ public class ApplicationRadio extends Radio implements PolledBeforeActiveTicks {
   public Mote getMote() {
     return myMote;
   }
+
+  public boolean isReceiverOn() {
+    return true;
+  }
 }
diff --git a/tools/cooja/java/se/sics/cooja/interfaces/Radio.java b/tools/cooja/java/se/sics/cooja/interfaces/Radio.java
index 41644c658..1724ef390 100644
--- a/tools/cooja/java/se/sics/cooja/interfaces/Radio.java
+++ b/tools/cooja/java/se/sics/cooja/interfaces/Radio.java
@@ -24,7 +24,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- * $Id: Radio.java,v 1.9 2008/03/18 13:01:13 fros4943 Exp $
+ * $Id: Radio.java,v 1.10 2009/04/16 14:26:36 fros4943 Exp $
  */
 
 package se.sics.cooja.interfaces;
@@ -119,6 +119,8 @@ public abstract class Radio extends MoteInterface {
    */
   public abstract boolean isInterfered();
 
+  public abstract boolean isReceiverOn();
+
   /**
    * Interferes with any current reception. If this method is called, the packet
    * will be dropped. This method can be used to simulate radio interference
diff --git a/tools/cooja/java/se/sics/cooja/motes/DisturberRadio.java b/tools/cooja/java/se/sics/cooja/motes/DisturberRadio.java
index 5fe54c320..50fcd1b00 100644
--- a/tools/cooja/java/se/sics/cooja/motes/DisturberRadio.java
+++ b/tools/cooja/java/se/sics/cooja/motes/DisturberRadio.java
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: DisturberRadio.java,v 1.10 2009/03/09 15:38:10 fros4943 Exp $
+ * $Id: DisturberRadio.java,v 1.11 2009/04/16 14:26:35 fros4943 Exp $
  */
 
 package se.sics.cooja.motes;
@@ -269,4 +269,8 @@ public class DisturberRadio extends Radio implements PolledBeforeAllTicks {
   public Mote getMote() {
     return myMote;
   }
+
+  public boolean isReceiverOn() {
+    return true;
+  }
 }
diff --git a/tools/cooja/java/se/sics/cooja/plugins/skins/UDGMVisualizerSkin.java b/tools/cooja/java/se/sics/cooja/plugins/skins/UDGMVisualizerSkin.java
index c28e4e95e..064266c82 100644
--- a/tools/cooja/java/se/sics/cooja/plugins/skins/UDGMVisualizerSkin.java
+++ b/tools/cooja/java/se/sics/cooja/plugins/skins/UDGMVisualizerSkin.java
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: UDGMVisualizerSkin.java,v 1.4 2009/04/14 15:40:26 fros4943 Exp $
+ * $Id: UDGMVisualizerSkin.java,v 1.5 2009/04/16 14:26:35 fros4943 Exp $
  */
 
 package se.sics.cooja.plugins.skins;
@@ -52,7 +52,6 @@ import se.sics.cooja.ClassDescription;
 import se.sics.cooja.Mote;
 import se.sics.cooja.RadioConnection;
 import se.sics.cooja.Simulation;
-import se.sics.cooja.contikimote.interfaces.ContikiRadio;
 import se.sics.cooja.interfaces.Position;
 import se.sics.cooja.interfaces.Radio;
 import se.sics.cooja.plugins.Visualizer;
@@ -296,7 +295,7 @@ public class UDGMVisualizerSkin implements VisualizerSkin {
       return new Color[] { Color.CYAN };
     }
 
-    if (moteRadio instanceof ContikiRadio && !((ContikiRadio) moteRadio).isOn()) {
+    if (!moteRadio.isReceiverOn()) {
       return new Color[] { Color.GRAY };
     }
 
diff --git a/tools/cooja/java/se/sics/cooja/radiomediums/UDGM.java b/tools/cooja/java/se/sics/cooja/radiomediums/UDGM.java
index 3b4461752..d9d3709b1 100644
--- a/tools/cooja/java/se/sics/cooja/radiomediums/UDGM.java
+++ b/tools/cooja/java/se/sics/cooja/radiomediums/UDGM.java
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: UDGM.java,v 1.23 2009/03/24 15:46:46 fros4943 Exp $
+ * $Id: UDGM.java,v 1.24 2009/04/16 14:26:35 fros4943 Exp $
  */
 
 package se.sics.cooja.radiomediums;
@@ -120,6 +120,9 @@ public class UDGM extends AbstractRadioMedium {
           sendingRadio.getChannel() != listeningRadio.getChannel()) {
         continue;
       }
+      if (!listeningRadio.isReceiverOn()) {
+        continue;
+      }
 
       double distance = sendingPosition.getDistanceTo(listeningRadioPosition);