diff --git a/TestBenchFramework/BenchControl/TestMethods/iPerlCommunication/iPerlCommunicationForm.cs b/TestBenchFramework/BenchControl/TestMethods/iPerlCommunication/iPerlCommunicationForm.cs
index 79be0dbf0..94d97a0b9 100644
--- a/TestBenchFramework/BenchControl/TestMethods/iPerlCommunication/iPerlCommunicationForm.cs
+++ b/TestBenchFramework/BenchControl/TestMethods/iPerlCommunication/iPerlCommunicationForm.cs
@@ -101,13 +101,13 @@ namespace TBF.BenchControl.TestMethods.iPerlCommunication
         /// RFID multiplexer PCB / RFID serial port and worker thread related variables
         ///
         static string activity;
-        static int currentGroup;                   /// form -> worker thread (0 = none)
+        static int currentGroup;                    /// form -> worker thread (0 = none)
         static int lastGroup;
+        static int completedCommCount;              /// Number of completed communication steps
 
         static IList<Thread> workerThreads;
         static IList<int> rfidPortNrs;
-        static IList<bool> stopWorkerThreads;      /// form -> worker thread
-
+        static IList<bool> stopWorkerThreads;       /// form -> worker thread
 
 		/// <summary> Parameterless constructor for 3 watermeters </summary>
 		public iPerlCommunicationForm()
@@ -145,6 +145,7 @@ namespace TBF.BenchControl.TestMethods.iPerlCommunication
 
             currentGroup = 0;
             lastGroup = 0;      /// group numbers are >=1, lastGroup == 0 means no group
+            completedCommCount = 0;
 
             workerThreads = new List<Thread>();
             rfidPortNrs = new List<int>();
@@ -201,14 +202,12 @@ namespace TBF.BenchControl.TestMethods.iPerlCommunication
                 if (iPerlWM.Group > lastGroup) lastGroup = iPerlWM.Group;
                 if (!rfidPortNrs.Contains(iPerlWM.RfidComPortNr))
                 {
+                    int threadId = workerThreads.Count;
+                    Thread thread = new Thread(iPerlCommunicationForm.Worker);
+                    workerThreads.Add(thread);
                     rfidPortNrs.Add(iPerlWM.RfidComPortNr);
-                    if (workerThreads.Count < 1)
-                    {
-                        Thread thread = new Thread(iPerlCommunicationForm.Worker);
-                        workerThreads.Add(thread);
-                        stopWorkerThreads.Add(false);
-                        thread.Start();             /// TODO: start with arguments: thread.Start(workerThreads.Count - 1);
-                    }
+                    stopWorkerThreads.Add(false);
+                    thread.Start(new Boxes.IntBox(threadId));
                 }
             }
 
@@ -352,9 +351,9 @@ namespace TBF.BenchControl.TestMethods.iPerlCommunication
 		#endregion
 
 
-        static void Worker()
+        static void Worker(object threadData)
         {
-            int threadId = 0;
+            int threadId = (threadData as Boxes.IntBox).Val;
             int rfidPortNr = rfidPortNrs[threadId];
 
             for (int group = 1; group <= lastGroup; group++)
@@ -364,10 +363,12 @@ namespace TBF.BenchControl.TestMethods.iPerlCommunication
                 if (stopWorkerThreads[threadId]) break;
 
                 int wmNr = 0;
+                bool wmFound = false;
                 foreach (var wm in waterMeters)
                 {
                     if ((wm.RfidComPortNr == rfidPortNr) && (wm.Group == group))
                     {
+                        wmFound = true;
                         if (wm.DebugLevel == Entities.DebugMode.Normal)
                         {
                             if (activity.Equals("Read configuration")) ReadConfig(wm, threadId, wmNr);
@@ -383,9 +384,12 @@ namespace TBF.BenchControl.TestMethods.iPerlCommunication
                     }
                     wmNr++;
                 }
+
+                if (!wmFound) OnCommCompleted(null, new CommCompletedEventArgs(threadId, -1, string.Empty));    /// Send negative wmNr
             }
         }
 
+
         static void ReadConfig(WaterMeters.iPerl.WaterMeter wm, int threadId, int wmNr)
         {
             bool success = (0 == openPort(wm.RfidComPortNr));   /// Open RFID port
@@ -414,6 +418,7 @@ namespace TBF.BenchControl.TestMethods.iPerlCommunication
             }
         }
 
+
         static void SetToTestMode(WaterMeters.iPerl.WaterMeter wm, int threadId, int wmNr)
         {
             bool success = (openPort(wm.RfidComPortNr) == 0);   /// Open RFID port
@@ -454,6 +459,7 @@ namespace TBF.BenchControl.TestMethods.iPerlCommunication
             }
         }
 
+
         static void SetToActiveMode(WaterMeters.iPerl.WaterMeter wm, int threadId, int wmNr)
         {
             bool success = (openPort(wm.RfidComPortNr) == 0);   /// Open RFID port
@@ -508,19 +514,27 @@ namespace TBF.BenchControl.TestMethods.iPerlCommunication
 
         void DoOnCommCompleted(object sender, CommCompletedEventArgs data)
         {
-            messages[data.WMNr].Text = data.CommMessage;
+            if (data.WMNr >= 0) messages[data.WMNr].Text = data.CommMessage;
+
+            lock (this)
+            {
+                if (++completedCommCount < workerThreads.Count) return;
+                completedCommCount = 0;
+            }
 
             if (currentGroup < lastGroup)
             {
+                /// Go to the next step / next group
                 if (quido != null)
                 {
                     quido.SetOutputs((ushort)(16 - currentGroup - 1));
-                    Thread.Sleep(200);
+                    Thread.Sleep(100);
                 }
                 currentGroup++;
             }
             else
             {
+                /// Wait until all threads are finished
                 workerThreads[data.ThreadId].Join(2000);
                 NormalClose();
             }