diff --git a/DataStreamInterface/IDataStreamMeter.cs b/DataStreamInterface/IDataStreamMeter.cs
index 922af4ec4..e4868b009 100644
--- a/DataStreamInterface/IDataStreamMeter.cs
+++ b/DataStreamInterface/IDataStreamMeter.cs
@@ -7,49 +7,77 @@ namespace DataStreamInterface
 {
     public interface IDataStreamMeter
     {
+        /// <summary>
+        /// Returns count of water meters supported by the data stream component
+        /// </summary>
+        /// <returns>Water meters count</returns>
+        int GetMetersCount();
+
         /// <summary>
         /// Get state of the connected data stream meter
         /// </summary>
+        /// <param name="meterIx">Index of the meter in range 0 .. (GetMetersCount() - 1)</param>
         /// <param name="state">Current state of the meter</param>
+        /// <param name="parameter">Current extra parameter of the meter</param>
         /// <returns>true when successful</returns>
-        bool GetState(out int state, out string parameter);
+        bool GetState(int meterIx, out int state, out string parameter);
 
         /// <summary>
         /// Set state of the connected data stream meter
         /// </summary>
+        /// <param name="meterIx">Index of the meter in range 0 .. (GetMetersCount() - 1)</param>
         /// <param name="state">Required state of the meter</param>
+        /// <param name="parameter">Required extra parameter of the meter</param>
         /// <returns>true when successful</returns>
-        bool SetState(int state, string parameter);
+        bool SetState(int meterIx, int state, string parameter);
+
+        bool SetStateAll(int state, string parameter);
 
         /// <summary>
         /// Establish connection with a data stream meter
         /// </summary>
+        /// <param name="meterIx">Index of the meter in range 0 .. (GetMetersCount() - 1)</param>
         /// <param name="connectionParameters">Connection parameters</param>
         /// <param name="meterId">Meter ID (e.g. serial number)</param>
         /// <returns>true when successful</returns>
-        bool OpenConnection(string connectionParameters, out string meterId);
-
-        /// <summary>
-        /// Closes connection with the data stream meter
-        /// </summary>
-        /// <returns>true when successful</returns>
-        bool CloseConnection();
+        bool OpenConnection(int meterIx, string connectionParameters, out string meterId);
 
         /// <summary>
         /// Stars saving measurement results into internal data structures of the component.
         /// Each data frame obtains a unique ID.
         /// The very first data fraim obrains ID = 0.
         /// </summary>
+        /// <param name="meterIx">Index of the meter in range 0 .. (GetMetersCount() - 1)</param>
         /// <returns>true when successful</returns>
-        bool StartMeasurement();
+        bool StartMeasurement(int meterIx);
+
+        bool StartMeasurementAll();
 
         /// <summary>
         /// Stops saving measurement results into internal data structures of the component.
         /// Updates ID of the last date frame received from the meter.
         /// </summary>
+        /// <param name="meterIx">Index of the meter in range 0 .. (GetMetersCount() - 1)</param>
         /// <param name="storedFramesCount">Number of stored date frames</param>
         /// <returns>true when successful</returns>
-        bool StopMeasurement(out Int64 storedFramesCount);
+        bool StopMeasurement(int meterIx, out Int64 storedFramesCount);
+
+        bool StopMeasurementAll(out Int64[] storedFramesCounts);
+
+        /// <summary>
+        /// Closes connection with the data stream meter
+        /// </summary>
+        /// <param name="meterIx">Index of the meter in range 0 .. (GetMetersCount() - 1)</param>
+        /// <returns>true when successful</returns>
+        bool CloseConnection(int meterIx);
+
+        bool CloseConnectionAll();
+
+        /// <summary>
+        /// This function is called when TBF program is shutting down.
+        /// </summary>
+        /// <returns>true when successful</returns>
+        bool Shutdown();
 
         ///------------------------------------------------
         /// Units of time, volume and optional quantities
@@ -94,17 +122,19 @@ namespace DataStreamInterface
         /// <summary>
         /// Retuns 'count' data frames starting with data frame with ID = 'id' 
         /// </summary>
+        /// <param name="meterIx">Index of the meter in range 0 .. (GetMetersCount() - 1)</param>
         /// <param name="id">First frame ID</param>
         /// <param name="count">Frames count</param>
         /// <returns>Selected data frames</returns>
-        DataFrame[] GetFrames(Int64 id, int count);
+        DataFrame[] GetFrames(int meterIx, Int64 id, int count);
 
         /// <summary>
         /// Returns ID of the data frame where time equals or exceeds the specified time.
         /// When time of the first frame (ID=0) is larger then specified time, function returns 0.
         /// </summary>
+        /// <param name="meterIx">Index of the meter in range 0 .. (GetMetersCount() - 1)</param>
         /// <param name="time">Time</param>
         /// <returns>ID of the data frame at or after the pecified time</returns>
-        Int64 GetID(double time);
+        Int64 GetID(int meterIx, double time);
     }
 }
diff --git a/DataStreamInterfaceTest/DemoMainWnd.Designer.cs b/DataStreamInterfaceTest/DemoMainWnd.Designer.cs
index f87a15e46..21db23d47 100644
--- a/DataStreamInterfaceTest/DemoMainWnd.Designer.cs
+++ b/DataStreamInterfaceTest/DemoMainWnd.Designer.cs
@@ -49,8 +49,8 @@
             this.logsTextBox = new System.Windows.Forms.TextBox();
             this.dataTabControl = new System.Windows.Forms.TabControl();
             this.tabPage1 = new System.Windows.Forms.TabPage();
-            this.tabPage2 = new System.Windows.Forms.TabPage();
             this.framesListView = new System.Windows.Forms.ListView();
+            this.tabPage2 = new System.Windows.Forms.TabPage();
             ((System.ComponentModel.ISupportInitialize)(this.splitContainer1)).BeginInit();
             this.splitContainer1.Panel1.SuspendLayout();
             this.splitContainer1.Panel2.SuspendLayout();
@@ -304,16 +304,6 @@
             this.tabPage1.Text = "Transferred frames";
             this.tabPage1.UseVisualStyleBackColor = true;
             // 
-            // tabPage2
-            // 
-            this.tabPage2.Location = new System.Drawing.Point(4, 22);
-            this.tabPage2.Name = "tabPage2";
-            this.tabPage2.Padding = new System.Windows.Forms.Padding(3);
-            this.tabPage2.Size = new System.Drawing.Size(664, 331);
-            this.tabPage2.TabIndex = 1;
-            this.tabPage2.Text = "Graph";
-            this.tabPage2.UseVisualStyleBackColor = true;
-            // 
             // framesListView
             // 
             this.framesListView.Dock = System.Windows.Forms.DockStyle.Fill;
@@ -325,6 +315,16 @@
             this.framesListView.UseCompatibleStateImageBehavior = false;
             this.framesListView.View = System.Windows.Forms.View.Details;
             // 
+            // tabPage2
+            // 
+            this.tabPage2.Location = new System.Drawing.Point(4, 22);
+            this.tabPage2.Name = "tabPage2";
+            this.tabPage2.Padding = new System.Windows.Forms.Padding(3);
+            this.tabPage2.Size = new System.Drawing.Size(664, 331);
+            this.tabPage2.TabIndex = 1;
+            this.tabPage2.Text = "Graph";
+            this.tabPage2.UseVisualStyleBackColor = true;
+            // 
             // DemoMainWnd
             // 
             this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
@@ -333,6 +333,7 @@
             this.Controls.Add(this.splitContainer1);
             this.Name = "DemoMainWnd";
             this.Text = "Datastream interface test";
+            this.FormClosing += new System.Windows.Forms.FormClosingEventHandler(this.DemoMainWnd_FormClosing);
             this.splitContainer1.Panel1.ResumeLayout(false);
             this.splitContainer1.Panel1.PerformLayout();
             this.splitContainer1.Panel2.ResumeLayout(false);
diff --git a/DataStreamInterfaceTest/DemoMainWnd.cs b/DataStreamInterfaceTest/DemoMainWnd.cs
index af1252f38..87567a7c8 100644
--- a/DataStreamInterfaceTest/DemoMainWnd.cs
+++ b/DataStreamInterfaceTest/DemoMainWnd.cs
@@ -127,7 +127,7 @@ namespace DataStreamInterfaceTest
             else
             {
                 string meterId;
-                if (dataStreamMeter.OpenConnection("no connection parameters", out meterId))
+                if (dataStreamMeter.OpenConnection(0, "no connection parameters", out meterId))
                 {
                     activityLog.Print(string.Format("Connection established, meter ID is {0}", meterId));
                 }
@@ -144,7 +144,7 @@ namespace DataStreamInterfaceTest
                 ShowNoMeterInterfaceMessage();
             else
             {
-                if (dataStreamMeter.CloseConnection())
+                if (dataStreamMeter.CloseConnection(0))
                 {
                     framesListView.Items.Clear();
                     activityLog.Print("Connection closed");
@@ -156,6 +156,14 @@ namespace DataStreamInterfaceTest
             }
         }
 
+        private void DemoMainWnd_FormClosing(object sender, FormClosingEventArgs e)
+        {
+            if (dataStreamMeter == null)
+            {
+                dataStreamMeter.Shutdown();
+            }
+        }
+
         private void getStateButton_Click(object sender, EventArgs e)
         {
             if (dataStreamMeter == null)
@@ -164,7 +172,7 @@ namespace DataStreamInterfaceTest
             {
                 int state;
                 string parameter;
-                if (dataStreamMeter.GetState(out state, out parameter))
+                if (dataStreamMeter.GetState(0, out state, out parameter))
                 {
                     activityLog.Print(string.Format("Water meter state is {0} / {1}", state, parameter));
                 }
@@ -184,7 +192,7 @@ namespace DataStreamInterfaceTest
                 GetStateDlg dlg = new GetStateDlg();
                 if (dlg.ShowDialog() == DialogResult.OK)
                 {
-                    if (dataStreamMeter.SetState(dlg.State, dlg.Parameter))
+                    if (dataStreamMeter.SetState(0, dlg.State, dlg.Parameter))
                     {
                         activityLog.Print(string.Format("Water meter state set to {0} / {1}", dlg.State, dlg.Parameter));
                     }
@@ -202,7 +210,7 @@ namespace DataStreamInterfaceTest
                 ShowNoMeterInterfaceMessage();
             else
             {
-                if (dataStreamMeter.StartMeasurement())
+                if (dataStreamMeter.StartMeasurement(0))
                 {
                     framesListView.Items.Clear();
                     activityLog.Print(string.Format("Measurement started"));
@@ -220,7 +228,7 @@ namespace DataStreamInterfaceTest
                 ShowNoMeterInterfaceMessage();
             else
             {
-                if (dataStreamMeter.StopMeasurement(out storedFramesCount))
+                if (dataStreamMeter.StopMeasurement(0, out storedFramesCount))
                 {
                     framesListView.Items.Clear();
                     activityLog.Print(string.Format("Measurement sopped, {0} frames acquired", storedFramesCount));
@@ -240,7 +248,7 @@ namespace DataStreamInterfaceTest
             {
                 GetFrameBoundariesDlg dlg = new GetFrameBoundariesDlg("Enter frames range boundaries", 0, storedFramesCount - 1);
                 if (dlg.ShowDialog() != DialogResult.OK) return;
-                DataFrame[] frames = dataStreamMeter.GetFrames(dlg.From, Convert.ToInt32(dlg.To - dlg.From + 1));
+                DataFrame[] frames = dataStreamMeter.GetFrames(0, dlg.From, Convert.ToInt32(dlg.To - dlg.From + 1));
                 {
                     foreach (var frame in frames)
                     {
@@ -259,7 +267,7 @@ namespace DataStreamInterfaceTest
                 GetDblValueDlg dlg = new GetDblValueDlg("Enter time in seconds");
                 if (dlg.ShowDialog() == DialogResult.OK)
                 {
-                    Int64 id = dataStreamMeter.GetID(dlg.DblValue);
+                    Int64 id = dataStreamMeter.GetID(0, dlg.DblValue);
                     activityLog.Print(string.Format("GetID({0}) returned {1}", dlg.DblValue, id));
                 }
             }
diff --git a/DataStreamMeter/MeterSimulation.cs b/DataStreamMeter/MeterSimulation.cs
index 81b023bde..823fe5602 100644
--- a/DataStreamMeter/MeterSimulation.cs
+++ b/DataStreamMeter/MeterSimulation.cs
@@ -83,7 +83,13 @@ namespace DataStreamMeter
             return Unit.None;
         }
 
-        public bool OpenConnection(string connectionParameters, out string meterID)
+
+        public int GetMetersCount()
+        {
+            return 1;
+        }
+
+        public bool OpenConnection(int meterIx, string connectionParameters, out string meterID)
         {
             lock (stateChangeAndTimerTickLock)
             {
@@ -107,7 +113,7 @@ namespace DataStreamMeter
             return true;
         }
 
-        public bool CloseConnection()
+        public bool CloseConnection(int meterIx)
         {
             bool closeModelessDlg = false;
 
@@ -129,20 +135,35 @@ namespace DataStreamMeter
             return true;
         }
 
-        public bool GetState(out int state, out string parameter)
+        public bool CloseConnectionAll()
+        {
+            return CloseConnection(0);
+        }
+
+        public bool Shutdown()
+        {
+            return true;
+        }
+
+        public bool GetState(int meterIx, out int state, out string parameter)
         {
             state = (int)this.State;
             parameter = this.connectionParameters;
             return true;
         }
 
-        public bool SetState(int state, string parameter)
+        public bool SetState(int meterIx, int state, string parameter)
         {
             /// It's not allowed to change the satate in this demo
             return false;
         }
 
-        public bool StartMeasurement()
+        public bool SetStateAll(int state, string parameter)
+        {
+            return SetState(0, state, parameter);
+        }
+
+        public bool StartMeasurement(int meterIx = 0)
         {
             lock (stateChangeAndTimerTickLock)
             {
@@ -161,7 +182,12 @@ namespace DataStreamMeter
             }
         }
 
-        public bool StopMeasurement(out Int64 storedFramesCount)
+        public bool StartMeasurementAll()
+        {
+            return StartMeasurement(0);
+        }
+
+        public bool StopMeasurement(int meterIx, out Int64 storedFramesCount)
         {
             lock (stateChangeAndTimerTickLock)
             {
@@ -196,6 +222,12 @@ namespace DataStreamMeter
             }
         }
 
+        public bool StopMeasurementAll(out Int64[] storedFramesCount)
+        {
+            storedFramesCount = new Int64[1];
+            return StopMeasurement(0, out storedFramesCount[0]);
+        }
+
         public void TimerTick(double flow_m3ph)
         {
             lock (stateChangeAndTimerTickLock)
@@ -259,7 +291,7 @@ namespace DataStreamMeter
         /// <param name="id">First frame ID</param>
         /// <param name="count">Frames count</param>
         /// <returns>Selected data frames</returns>
-        public DataFrame[] GetFrames(Int64 startID, int count)
+        public DataFrame[] GetFrames(int meterIx, Int64 startID, int count)
         {
             DataFrame[] frames = new DataFrame[count];
 
@@ -284,7 +316,7 @@ namespace DataStreamMeter
         /// </summary>
         /// <param name="time">Time</param>
         /// <returns>ID of the data frame at or after the pecified time</returns>
-        public Int64 GetID(double time)
+        public Int64 GetID(int meterIx, double time)
         {
             if (storedSamplesCount == 0) return -1;