diff --git a/plugins/samplesink/bladerfoutput/bladerfoutput.cpp b/plugins/samplesink/bladerfoutput/bladerfoutput.cpp
index 115853294..66dfd818e 100644
--- a/plugins/samplesink/bladerfoutput/bladerfoutput.cpp
+++ b/plugins/samplesink/bladerfoutput/bladerfoutput.cpp
@@ -211,7 +211,7 @@ bool BladerfOutput::handleMessage(const Message& message)
 	if (MsgConfigureBladerf::match(message))
 	{
 		MsgConfigureBladerf& conf = (MsgConfigureBladerf&) message;
-		qDebug() << "BladerfInput::handleMessage: MsgConfigureBladerf";
+		qDebug() << "BladerfOutput::handleMessage: MsgConfigureBladerf";
 
 		if (!applySettings(conf.getSettings(), conf.getForce()))
 		{
@@ -223,7 +223,7 @@ bool BladerfOutput::handleMessage(const Message& message)
     else if (MsgStartStop::match(message))
     {
         MsgStartStop& cmd = (MsgStartStop&) message;
-        qDebug() << "SDRPlayInput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");
+        qDebug() << "BladerfOutput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");
 
         if (cmd.getStartStop())
         {
diff --git a/plugins/samplesink/bladerfoutput/bladerfoutputgui.cpp b/plugins/samplesink/bladerfoutput/bladerfoutputgui.cpp
index 3ddc65e8d..b1abe2fe5 100644
--- a/plugins/samplesink/bladerfoutput/bladerfoutputgui.cpp
+++ b/plugins/samplesink/bladerfoutput/bladerfoutputgui.cpp
@@ -132,6 +132,14 @@ bool BladerfOutputGui::handleMessage(const Message& message)
 		displaySettings();
 		return true;
 	}
+    else if (BladerfOutput::MsgStartStop::match(message))
+    {
+        BladerfOutput::MsgStartStop& notif = (BladerfOutput::MsgStartStop&) message;
+        blockApplySettings(true);
+        ui->startStop->setChecked(notif.getStartStop());
+        blockApplySettings(false);
+        return true;
+    }
 	else
 	{
 		return false;
diff --git a/plugins/samplesink/hackrfoutput/hackrfoutput.cpp b/plugins/samplesink/hackrfoutput/hackrfoutput.cpp
index 4f9a8dbda..dd2bcd71f 100644
--- a/plugins/samplesink/hackrfoutput/hackrfoutput.cpp
+++ b/plugins/samplesink/hackrfoutput/hackrfoutput.cpp
@@ -18,6 +18,7 @@
 
 #include <string.h>
 #include <errno.h>
+#include <unistd.h>
 #include <QDebug>
 
 #include "SWGDeviceSettings.h"
@@ -34,6 +35,7 @@
 #include "hackrfoutputthread.h"
 
 MESSAGE_CLASS_DEFINITION(HackRFOutput::MsgConfigureHackRF, Message)
+MESSAGE_CLASS_DEFINITION(HackRFOutput::MsgStartStop, Message)
 MESSAGE_CLASS_DEFINITION(HackRFOutput::MsgReportHackRF, Message)
 
 HackRFOutput::HackRFOutput(DeviceSinkAPI *deviceAPI) :
@@ -205,6 +207,27 @@ bool HackRFOutput::handleMessage(const Message& message)
 
         return true;
     }
+    else if (MsgStartStop::match(message))
+    {
+        MsgStartStop& cmd = (MsgStartStop&) message;
+        qDebug() << "HackRFOutput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");
+
+        if (cmd.getStartStop())
+        {
+            if (m_deviceAPI->initGeneration())
+            {
+                m_deviceAPI->startGeneration();
+                DSPEngine::instance()->startAudioInput();
+            }
+        }
+        else
+        {
+            m_deviceAPI->stopGeneration();
+            DSPEngine::instance()->stopAudioInput();
+        }
+
+        return true;
+    }
 	else
 	{
 		return false;
@@ -413,19 +436,16 @@ int HackRFOutput::webapiRun(
         SWGSDRangel::SWGDeviceState& response,
         QString& errorMessage __attribute__((unused)))
 {
-    if (run)
+    MsgStartStop *message = MsgStartStop::create(run);
+    m_inputMessageQueue.push(message);
+
+    if (m_guiMessageQueue)
     {
-        if (m_deviceAPI->initGeneration())
-        {
-            m_deviceAPI->startGeneration();
-            DSPEngine::instance()->startAudioInputImmediate();
-        }
-    }
-    else
-    {
-        m_deviceAPI->stopGeneration();
+        MsgStartStop *messagetoGui = MsgStartStop::create(run);
+        m_guiMessageQueue->push(messagetoGui);
     }
 
+    usleep(100000);
     m_deviceAPI->getDeviceEngineStateStr(*response.getState());
     return 200;
 }
diff --git a/plugins/samplesink/hackrfoutput/hackrfoutput.h b/plugins/samplesink/hackrfoutput/hackrfoutput.h
index aa6778e1a..c18370530 100644
--- a/plugins/samplesink/hackrfoutput/hackrfoutput.h
+++ b/plugins/samplesink/hackrfoutput/hackrfoutput.h
@@ -54,6 +54,25 @@ public:
 		{ }
 	};
 
+    class MsgStartStop : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        bool getStartStop() const { return m_startStop; }
+
+        static MsgStartStop* create(bool startStop) {
+            return new MsgStartStop(startStop);
+        }
+
+    protected:
+        bool m_startStop;
+
+        MsgStartStop(bool startStop) :
+            Message(),
+            m_startStop(startStop)
+        { }
+    };
+
 	class MsgReportHackRF : public Message {
 		MESSAGE_CLASS_DECLARATION
 
diff --git a/plugins/samplesink/hackrfoutput/hackrfoutputgui.cpp b/plugins/samplesink/hackrfoutput/hackrfoutputgui.cpp
index 4675f8d4f..5c877d324 100644
--- a/plugins/samplesink/hackrfoutput/hackrfoutputgui.cpp
+++ b/plugins/samplesink/hackrfoutput/hackrfoutputgui.cpp
@@ -136,6 +136,14 @@ bool HackRFOutputGui::handleMessage(const Message& message)
         displaySettings();
         return true;
     }
+    else if (HackRFOutput::MsgStartStop::match(message))
+    {
+        HackRFOutput::MsgStartStop& notif = (HackRFOutput::MsgStartStop&) message;
+        blockApplySettings(true);
+        ui->startStop->setChecked(notif.getStartStop());
+        blockApplySettings(false);
+        return true;
+    }
     else
     {
         return false;
@@ -298,25 +306,10 @@ void HackRFOutputGui::on_txvga_valueChanged(int value)
 
 void HackRFOutputGui::on_startStop_toggled(bool checked)
 {
-    if (checked)
+    if (m_doApplySettings)
     {
-        // forcibly stop the Rx if present before starting
-        if (m_deviceUISet->m_deviceSinkAPI->getSourceBuddies().size() > 0)
-        {
-            DeviceSourceAPI *buddy = m_deviceUISet->m_deviceSinkAPI->getSourceBuddies()[0];
-            buddy->stopAcquisition();
-        }
-
-        if (m_deviceUISet->m_deviceSinkAPI->initGeneration())
-        {
-            m_deviceUISet->m_deviceSinkAPI->startGeneration();
-            DSPEngine::instance()->startAudioInput();
-        }
-    }
-    else
-    {
-        m_deviceUISet->m_deviceSinkAPI->stopGeneration();
-        DSPEngine::instance()->startAudioInput();
+        HackRFOutput::MsgStartStop *message = HackRFOutput::MsgStartStop::create(checked);
+        m_deviceSampleSink->getInputMessageQueue()->push(message);
     }
 }
 
diff --git a/plugins/samplesink/limesdroutput/limesdroutput.cpp b/plugins/samplesink/limesdroutput/limesdroutput.cpp
index d75c30c52..b4c273d2b 100644
--- a/plugins/samplesink/limesdroutput/limesdroutput.cpp
+++ b/plugins/samplesink/limesdroutput/limesdroutput.cpp
@@ -18,6 +18,7 @@
 #include <QDebug>
 #include <cstddef>
 #include <string.h>
+#include <unistd.h>
 #include "lime/LimeSuite.h"
 
 #include "SWGDeviceSettings.h"
@@ -34,6 +35,7 @@
 #include "limesdroutput.h"
 
 MESSAGE_CLASS_DEFINITION(LimeSDROutput::MsgConfigureLimeSDR, Message)
+MESSAGE_CLASS_DEFINITION(LimeSDROutput::MsgStartStop, Message)
 MESSAGE_CLASS_DEFINITION(LimeSDROutput::MsgGetStreamInfo, Message)
 MESSAGE_CLASS_DEFINITION(LimeSDROutput::MsgGetDeviceInfo, Message)
 MESSAGE_CLASS_DEFINITION(LimeSDROutput::MsgReportStreamInfo, Message)
@@ -467,6 +469,27 @@ bool LimeSDROutput::handleMessage(const Message& message)
 
         return true;
     }
+    else if (MsgStartStop::match(message))
+    {
+        MsgStartStop& cmd = (MsgStartStop&) message;
+        qDebug() << "LimeSDROutput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");
+
+        if (cmd.getStartStop())
+        {
+            if (m_deviceAPI->initGeneration())
+            {
+                m_deviceAPI->startGeneration();
+                DSPEngine::instance()->startAudioInput();
+            }
+        }
+        else
+        {
+            m_deviceAPI->stopGeneration();
+            DSPEngine::instance()->stopAudioInput();
+        }
+
+        return true;
+    }
     else if (DeviceLimeSDRShared::MsgReportBuddyChange::match(message))
     {
         DeviceLimeSDRShared::MsgReportBuddyChange& report = (DeviceLimeSDRShared::MsgReportBuddyChange&) message;
@@ -1093,19 +1116,16 @@ int LimeSDROutput::webapiRun(
         SWGSDRangel::SWGDeviceState& response,
         QString& errorMessage __attribute__((unused)))
 {
-    if (run)
+    MsgStartStop *message = MsgStartStop::create(run);
+    m_inputMessageQueue.push(message);
+
+    if (m_guiMessageQueue)
     {
-        if (m_deviceAPI->initGeneration())
-        {
-            m_deviceAPI->startGeneration();
-            DSPEngine::instance()->startAudioInputImmediate();
-        }
-    }
-    else
-    {
-        m_deviceAPI->stopGeneration();
+        MsgStartStop *messagetoGui = MsgStartStop::create(run);
+        m_guiMessageQueue->push(messagetoGui);
     }
 
+    usleep(100000);
     m_deviceAPI->getDeviceEngineStateStr(*response.getState());
     return 200;
 }
diff --git a/plugins/samplesink/limesdroutput/limesdroutput.h b/plugins/samplesink/limesdroutput/limesdroutput.h
index ce0f5d978..82a9c0705 100644
--- a/plugins/samplesink/limesdroutput/limesdroutput.h
+++ b/plugins/samplesink/limesdroutput/limesdroutput.h
@@ -54,6 +54,25 @@ public:
         { }
     };
 
+    class MsgStartStop : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        bool getStartStop() const { return m_startStop; }
+
+        static MsgStartStop* create(bool startStop) {
+            return new MsgStartStop(startStop);
+        }
+
+    protected:
+        bool m_startStop;
+
+        MsgStartStop(bool startStop) :
+            Message(),
+            m_startStop(startStop)
+        { }
+    };
+
     class MsgGetStreamInfo : public Message {
         MESSAGE_CLASS_DECLARATION
 
diff --git a/plugins/samplesink/limesdroutput/limesdroutputgui.cpp b/plugins/samplesink/limesdroutput/limesdroutputgui.cpp
index 71e121501..7b0148518 100644
--- a/plugins/samplesink/limesdroutput/limesdroutputgui.cpp
+++ b/plugins/samplesink/limesdroutput/limesdroutputgui.cpp
@@ -249,6 +249,14 @@ void LimeSDROutputGUI::handleInputMessages()
 
             delete message;
         }
+        else if (LimeSDROutput::MsgStartStop::match(*message))
+        {
+            LimeSDROutput::MsgStartStop& notif = (LimeSDROutput::MsgStartStop&) *message;
+            blockApplySettings(true);
+            ui->startStop->setChecked(notif.getStartStop());
+            blockApplySettings(false);
+            delete message;
+        }
         else
         {
             if (handleMessage(*message)) {
@@ -394,18 +402,10 @@ void LimeSDROutputGUI::blockApplySettings(bool block)
 
 void LimeSDROutputGUI::on_startStop_toggled(bool checked)
 {
-    if (checked)
+    if (m_doApplySettings)
     {
-        if (m_deviceUISet->m_deviceSinkAPI->initGeneration())
-        {
-            m_deviceUISet->m_deviceSinkAPI->startGeneration();
-            DSPEngine::instance()->startAudioInput();
-        }
-    }
-    else
-    {
-        m_deviceUISet->m_deviceSinkAPI->stopGeneration();
-        DSPEngine::instance()->stopAudioInput();
+        LimeSDROutput::MsgStartStop *message = LimeSDROutput::MsgStartStop::create(checked);
+        m_limeSDROutput->getInputMessageQueue()->push(message);
     }
 }
 
diff --git a/plugins/samplesink/plutosdroutput/plutosdroutput.cpp b/plugins/samplesink/plutosdroutput/plutosdroutput.cpp
index b1ec278ba..85ab01258 100644
--- a/plugins/samplesink/plutosdroutput/plutosdroutput.cpp
+++ b/plugins/samplesink/plutosdroutput/plutosdroutput.cpp
@@ -15,6 +15,7 @@
 ///////////////////////////////////////////////////////////////////////////////////
 
 #include <QDebug>
+#include <unistd.h>
 
 #include "SWGDeviceSettings.h"
 #include "SWGDeviceState.h"
@@ -32,6 +33,7 @@
 #define PLUTOSDR_BLOCKSIZE_SAMPLES (16*1024) //complex samples per buffer (must be multiple of 64)
 
 MESSAGE_CLASS_DEFINITION(PlutoSDROutput::MsgConfigurePlutoSDR, Message)
+MESSAGE_CLASS_DEFINITION(PlutoSDROutput::MsgStartStop, Message)
 
 PlutoSDROutput::PlutoSDROutput(DeviceSinkAPI *deviceAPI) :
     m_deviceAPI(deviceAPI),
@@ -145,6 +147,27 @@ bool PlutoSDROutput::handleMessage(const Message& message)
 
         return true;
     }
+    else if (MsgStartStop::match(message))
+    {
+        MsgStartStop& cmd = (MsgStartStop&) message;
+        qDebug() << "PlutoSDROutput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");
+
+        if (cmd.getStartStop())
+        {
+            if (m_deviceAPI->initGeneration())
+            {
+                m_deviceAPI->startGeneration();
+                DSPEngine::instance()->startAudioInput();
+            }
+        }
+        else
+        {
+            m_deviceAPI->stopGeneration();
+            DSPEngine::instance()->stopAudioInput();
+        }
+
+        return true;
+    }
     else
     {
         return false;
@@ -491,19 +514,16 @@ int PlutoSDROutput::webapiRun(
         SWGSDRangel::SWGDeviceState& response,
         QString& errorMessage __attribute__((unused)))
 {
-    if (run)
+    MsgStartStop *message = MsgStartStop::create(run);
+    m_inputMessageQueue.push(message);
+
+    if (m_guiMessageQueue)
     {
-        if (m_deviceAPI->initGeneration())
-        {
-            m_deviceAPI->startGeneration();
-            DSPEngine::instance()->startAudioInputImmediate();
-        }
-    }
-    else
-    {
-        m_deviceAPI->stopGeneration();
+        MsgStartStop *messagetoGui = MsgStartStop::create(run);
+        m_guiMessageQueue->push(messagetoGui);
     }
 
+    usleep(100000);
     m_deviceAPI->getDeviceEngineStateStr(*response.getState());
     return 200;
 }
diff --git a/plugins/samplesink/plutosdroutput/plutosdroutput.h b/plugins/samplesink/plutosdroutput/plutosdroutput.h
index 596da1f5c..037240c81 100644
--- a/plugins/samplesink/plutosdroutput/plutosdroutput.h
+++ b/plugins/samplesink/plutosdroutput/plutosdroutput.h
@@ -53,6 +53,25 @@ public:
         { }
     };
 
+    class MsgStartStop : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        bool getStartStop() const { return m_startStop; }
+
+        static MsgStartStop* create(bool startStop) {
+            return new MsgStartStop(startStop);
+        }
+
+    protected:
+        bool m_startStop;
+
+        MsgStartStop(bool startStop) :
+            Message(),
+            m_startStop(startStop)
+        { }
+    };
+
     PlutoSDROutput(DeviceSinkAPI *deviceAPI);
     ~PlutoSDROutput();
     virtual void destroy();
diff --git a/plugins/samplesink/plutosdroutput/plutosdroutputgui.cpp b/plugins/samplesink/plutosdroutput/plutosdroutputgui.cpp
index e6cc6be5c..6f92c1701 100644
--- a/plugins/samplesink/plutosdroutput/plutosdroutputgui.cpp
+++ b/plugins/samplesink/plutosdroutput/plutosdroutputgui.cpp
@@ -145,6 +145,14 @@ bool PlutoSDROutputGUI::handleMessage(const Message& message __attribute__((unus
 
         return true;
     }
+    else if (PlutoSDROutput::MsgStartStop::match(message))
+    {
+        PlutoSDROutput::MsgStartStop& notif = (PlutoSDROutput::MsgStartStop&) message;
+        blockApplySettings(true);
+        ui->startStop->setChecked(notif.getStartStop());
+        blockApplySettings(false);
+        return true;
+    }
     else
     {
         return false;
@@ -153,18 +161,10 @@ bool PlutoSDROutputGUI::handleMessage(const Message& message __attribute__((unus
 
 void PlutoSDROutputGUI::on_startStop_toggled(bool checked)
 {
-    if (checked)
+    if (m_doApplySettings)
     {
-        if (m_deviceUISet->m_deviceSinkAPI->initGeneration())
-        {
-            m_deviceUISet->m_deviceSinkAPI->startGeneration();
-            DSPEngine::instance()->startAudioOutput();
-        }
-    }
-    else
-    {
-        m_deviceUISet->m_deviceSinkAPI->stopGeneration();
-        DSPEngine::instance()->stopAudioOutput();
+        PlutoSDROutput::MsgStartStop *message = PlutoSDROutput::MsgStartStop::create(checked);
+        m_sampleSink->getInputMessageQueue()->push(message);
     }
 }
 
diff --git a/plugins/samplesink/sdrdaemonsink/sdrdaemonsinkgui.cpp b/plugins/samplesink/sdrdaemonsink/sdrdaemonsinkgui.cpp
index e08580194..9fa17cd3e 100644
--- a/plugins/samplesink/sdrdaemonsink/sdrdaemonsinkgui.cpp
+++ b/plugins/samplesink/sdrdaemonsink/sdrdaemonsinkgui.cpp
@@ -177,6 +177,14 @@ bool SDRdaemonSinkGui::handleMessage(const Message& message)
 		updateWithStreamTime();
 		return true;
 	}
+    else if (SDRdaemonSinkOutput::MsgStartStop::match(message))
+    {
+        SDRdaemonSinkOutput::MsgStartStop& notif = (SDRdaemonSinkOutput::MsgStartStop&) message;
+        blockApplySettings(true);
+        ui->startStop->setChecked(notif.getStartStop());
+        blockApplySettings(false);
+        return true;
+    }
 	else
 	{
 		return false;
@@ -499,22 +507,10 @@ void SDRdaemonSinkGui::on_sendButton_clicked(bool checked __attribute__((unused)
 
 void SDRdaemonSinkGui::on_startStop_toggled(bool checked)
 {
-    if (checked)
+    if (m_doApplySettings)
     {
-        if (m_deviceUISet->m_deviceSinkAPI->initGeneration())
-        {
-            if (!m_deviceUISet->m_deviceSinkAPI->startGeneration())
-            {
-                qDebug("SDRdaemonSinkGui::on_startStop_toggled: device start failed");
-            }
-
-            DSPEngine::instance()->startAudioInput();
-        }
-    }
-    else
-    {
-        m_deviceUISet->m_deviceSinkAPI->stopGeneration();
-        DSPEngine::instance()->stopAudioInput();
+        SDRdaemonSinkOutput::MsgStartStop *message = SDRdaemonSinkOutput::MsgStartStop::create(checked);
+        m_deviceSampleSink->getInputMessageQueue()->push(message);
     }
 }
 
diff --git a/plugins/samplesink/sdrdaemonsink/sdrdaemonsinkoutput.cpp b/plugins/samplesink/sdrdaemonsink/sdrdaemonsinkoutput.cpp
index 81be1adc8..65d083099 100644
--- a/plugins/samplesink/sdrdaemonsink/sdrdaemonsinkoutput.cpp
+++ b/plugins/samplesink/sdrdaemonsink/sdrdaemonsinkoutput.cpp
@@ -31,6 +31,7 @@
 
 MESSAGE_CLASS_DEFINITION(SDRdaemonSinkOutput::MsgConfigureSDRdaemonSink, Message)
 MESSAGE_CLASS_DEFINITION(SDRdaemonSinkOutput::MsgConfigureSDRdaemonSinkWork, Message)
+MESSAGE_CLASS_DEFINITION(SDRdaemonSinkOutput::MsgStartStop, Message)
 MESSAGE_CLASS_DEFINITION(SDRdaemonSinkOutput::MsgConfigureSDRdaemonSinkStreamTiming, Message)
 MESSAGE_CLASS_DEFINITION(SDRdaemonSinkOutput::MsgConfigureSDRdaemonSinkChunkCorrection, Message)
 MESSAGE_CLASS_DEFINITION(SDRdaemonSinkOutput::MsgReportSDRdaemonSinkStreamTiming, Message)
@@ -145,6 +146,27 @@ bool SDRdaemonSinkOutput::handleMessage(const Message& message)
 
 		return true;
 	}
+    else if (MsgStartStop::match(message))
+    {
+        MsgStartStop& cmd = (MsgStartStop&) message;
+        qDebug() << "SDRdaemonSinkOutput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");
+
+        if (cmd.getStartStop())
+        {
+            if (m_deviceAPI->initGeneration())
+            {
+                m_deviceAPI->startGeneration();
+                DSPEngine::instance()->startAudioInput();
+            }
+        }
+        else
+        {
+            m_deviceAPI->stopGeneration();
+            DSPEngine::instance()->stopAudioInput();
+        }
+
+        return true;
+    }
 	else if (MsgConfigureSDRdaemonSinkStreamTiming::match(message))
 	{
         MsgReportSDRdaemonSinkStreamTiming *report;
diff --git a/plugins/samplesink/sdrdaemonsink/sdrdaemonsinkoutput.h b/plugins/samplesink/sdrdaemonsink/sdrdaemonsinkoutput.h
index f1b4b362b..24af6f7a8 100644
--- a/plugins/samplesink/sdrdaemonsink/sdrdaemonsinkoutput.h
+++ b/plugins/samplesink/sdrdaemonsink/sdrdaemonsinkoutput.h
@@ -1,161 +1,180 @@
-///////////////////////////////////////////////////////////////////////////////////
-// Copyright (C) 2017 Edouard Griffiths, F4EXB                                   //
-//                                                                               //
-// 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 as version 3 of the License, or                  //
-//                                                                               //
-// 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 V3 for more details.                               //
-//                                                                               //
-// You should have received a copy of the GNU General Public License             //
-// along with this program. If not, see <http://www.gnu.org/licenses/>.          //
-///////////////////////////////////////////////////////////////////////////////////
-
-#ifndef INCLUDE_SDRDAEMONSINKOUTPUT_H
-#define INCLUDE_SDRDAEMONSINKOUTPUT_H
-
-#include <QString>
-#include <QTimer>
-#include <ctime>
-#include <iostream>
-#include <fstream>
-
-#include "dsp/devicesamplesink.h"
-
-#include "sdrdaemonsinksettings.h"
-
-class SDRdaemonSinkThread;
-class DeviceSinkAPI;
-
-class SDRdaemonSinkOutput : public DeviceSampleSink {
-public:
-	class MsgConfigureSDRdaemonSink : public Message {
-		MESSAGE_CLASS_DECLARATION
-
-	public:
-		const SDRdaemonSinkSettings& getSettings() const { return m_settings; }
-		bool getForce() const { return m_force; }
-
-		static MsgConfigureSDRdaemonSink* create(const SDRdaemonSinkSettings& settings, bool force = false)
-		{
-			return new MsgConfigureSDRdaemonSink(settings, force);
-		}
-
-	private:
-		SDRdaemonSinkSettings m_settings;
-		bool m_force;
-
-		MsgConfigureSDRdaemonSink(const SDRdaemonSinkSettings& settings, bool force) :
-			Message(),
-			m_settings(settings),
-			m_force(force)
-		{ }
-	};
-
-	class MsgConfigureSDRdaemonSinkWork : public Message {
-		MESSAGE_CLASS_DECLARATION
-
-	public:
-		bool isWorking() const { return m_working; }
-
-		static MsgConfigureSDRdaemonSinkWork* create(bool working)
-		{
-			return new MsgConfigureSDRdaemonSinkWork(working);
-		}
-
-	private:
-		bool m_working;
-
-		MsgConfigureSDRdaemonSinkWork(bool working) :
-			Message(),
-			m_working(working)
-		{ }
-	};
-
-    class MsgConfigureSDRdaemonSinkChunkCorrection : public Message {
-        MESSAGE_CLASS_DECLARATION
-
-    public:
-        int getChunkCorrection() const { return m_chunkCorrection; }
-
-        static MsgConfigureSDRdaemonSinkChunkCorrection* create(int chunkCorrection)
-        {
-            return new MsgConfigureSDRdaemonSinkChunkCorrection(chunkCorrection);
-        }
-
-    private:
-        int m_chunkCorrection;
-
-        MsgConfigureSDRdaemonSinkChunkCorrection(int chunkCorrection) :
-            Message(),
-            m_chunkCorrection(chunkCorrection)
-        { }
-    };
-
-	class MsgConfigureSDRdaemonSinkStreamTiming : public Message {
-		MESSAGE_CLASS_DECLARATION
-
-	public:
-
-		static MsgConfigureSDRdaemonSinkStreamTiming* create()
-		{
-			return new MsgConfigureSDRdaemonSinkStreamTiming();
-		}
-
-	private:
-
-		MsgConfigureSDRdaemonSinkStreamTiming() :
-			Message()
-		{ }
-	};
-
-	class MsgReportSDRdaemonSinkStreamTiming : public Message {
-		MESSAGE_CLASS_DECLARATION
-
-	public:
-		std::size_t getSamplesCount() const { return m_samplesCount; }
-
-		static MsgReportSDRdaemonSinkStreamTiming* create(std::size_t samplesCount)
-		{
-			return new MsgReportSDRdaemonSinkStreamTiming(samplesCount);
-		}
-
-	protected:
-		std::size_t m_samplesCount;
-
-		MsgReportSDRdaemonSinkStreamTiming(std::size_t samplesCount) :
-			Message(),
-			m_samplesCount(samplesCount)
-		{ }
-	};
-
-	SDRdaemonSinkOutput(DeviceSinkAPI *deviceAPI);
-	virtual ~SDRdaemonSinkOutput();
-	virtual void destroy();
-
-	virtual bool start();
-	virtual void stop();
-
-	virtual const QString& getDeviceDescription() const;
-	virtual int getSampleRate() const;
-	virtual quint64 getCenterFrequency() const;
-	std::time_t getStartingTimeStamp() const;
-
-	virtual bool handleMessage(const Message& message);
-
-private:
-    DeviceSinkAPI *m_deviceAPI;
-	QMutex m_mutex;
-	SDRdaemonSinkSettings m_settings;
-	SDRdaemonSinkThread* m_sdrDaemonSinkThread;
-	QString m_deviceDescription;
-	std::time_t m_startingTimeStamp;
-	const QTimer& m_masterTimer;
-
-	void applySettings(const SDRdaemonSinkSettings& settings, bool force = false);
-};
-
-#endif // INCLUDE_SDRDAEMONSINKOUTPUT_H
+///////////////////////////////////////////////////////////////////////////////////
+// Copyright (C) 2017 Edouard Griffiths, F4EXB                                   //
+//                                                                               //
+// 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 as version 3 of the License, or                  //
+//                                                                               //
+// 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 V3 for more details.                               //
+//                                                                               //
+// You should have received a copy of the GNU General Public License             //
+// along with this program. If not, see <http://www.gnu.org/licenses/>.          //
+///////////////////////////////////////////////////////////////////////////////////
+
+#ifndef INCLUDE_SDRDAEMONSINKOUTPUT_H
+#define INCLUDE_SDRDAEMONSINKOUTPUT_H
+
+#include <QString>
+#include <QTimer>
+#include <ctime>
+#include <iostream>
+#include <fstream>
+
+#include "dsp/devicesamplesink.h"
+
+#include "sdrdaemonsinksettings.h"
+
+class SDRdaemonSinkThread;
+class DeviceSinkAPI;
+
+class SDRdaemonSinkOutput : public DeviceSampleSink {
+public:
+	class MsgConfigureSDRdaemonSink : public Message {
+		MESSAGE_CLASS_DECLARATION
+
+	public:
+		const SDRdaemonSinkSettings& getSettings() const { return m_settings; }
+		bool getForce() const { return m_force; }
+
+		static MsgConfigureSDRdaemonSink* create(const SDRdaemonSinkSettings& settings, bool force = false)
+		{
+			return new MsgConfigureSDRdaemonSink(settings, force);
+		}
+
+	private:
+		SDRdaemonSinkSettings m_settings;
+		bool m_force;
+
+		MsgConfigureSDRdaemonSink(const SDRdaemonSinkSettings& settings, bool force) :
+			Message(),
+			m_settings(settings),
+			m_force(force)
+		{ }
+	};
+
+	class MsgConfigureSDRdaemonSinkWork : public Message {
+		MESSAGE_CLASS_DECLARATION
+
+	public:
+		bool isWorking() const { return m_working; }
+
+		static MsgConfigureSDRdaemonSinkWork* create(bool working)
+		{
+			return new MsgConfigureSDRdaemonSinkWork(working);
+		}
+
+	private:
+		bool m_working;
+
+		MsgConfigureSDRdaemonSinkWork(bool working) :
+			Message(),
+			m_working(working)
+		{ }
+	};
+
+    class MsgStartStop : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        bool getStartStop() const { return m_startStop; }
+
+        static MsgStartStop* create(bool startStop) {
+            return new MsgStartStop(startStop);
+        }
+
+    protected:
+        bool m_startStop;
+
+        MsgStartStop(bool startStop) :
+            Message(),
+            m_startStop(startStop)
+        { }
+    };
+
+    class MsgConfigureSDRdaemonSinkChunkCorrection : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        int getChunkCorrection() const { return m_chunkCorrection; }
+
+        static MsgConfigureSDRdaemonSinkChunkCorrection* create(int chunkCorrection)
+        {
+            return new MsgConfigureSDRdaemonSinkChunkCorrection(chunkCorrection);
+        }
+
+    private:
+        int m_chunkCorrection;
+
+        MsgConfigureSDRdaemonSinkChunkCorrection(int chunkCorrection) :
+            Message(),
+            m_chunkCorrection(chunkCorrection)
+        { }
+    };
+
+	class MsgConfigureSDRdaemonSinkStreamTiming : public Message {
+		MESSAGE_CLASS_DECLARATION
+
+	public:
+
+		static MsgConfigureSDRdaemonSinkStreamTiming* create()
+		{
+			return new MsgConfigureSDRdaemonSinkStreamTiming();
+		}
+
+	private:
+
+		MsgConfigureSDRdaemonSinkStreamTiming() :
+			Message()
+		{ }
+	};
+
+	class MsgReportSDRdaemonSinkStreamTiming : public Message {
+		MESSAGE_CLASS_DECLARATION
+
+	public:
+		std::size_t getSamplesCount() const { return m_samplesCount; }
+
+		static MsgReportSDRdaemonSinkStreamTiming* create(std::size_t samplesCount)
+		{
+			return new MsgReportSDRdaemonSinkStreamTiming(samplesCount);
+		}
+
+	protected:
+		std::size_t m_samplesCount;
+
+		MsgReportSDRdaemonSinkStreamTiming(std::size_t samplesCount) :
+			Message(),
+			m_samplesCount(samplesCount)
+		{ }
+	};
+
+	SDRdaemonSinkOutput(DeviceSinkAPI *deviceAPI);
+	virtual ~SDRdaemonSinkOutput();
+	virtual void destroy();
+
+	virtual bool start();
+	virtual void stop();
+
+	virtual const QString& getDeviceDescription() const;
+	virtual int getSampleRate() const;
+	virtual quint64 getCenterFrequency() const;
+	std::time_t getStartingTimeStamp() const;
+
+	virtual bool handleMessage(const Message& message);
+
+private:
+    DeviceSinkAPI *m_deviceAPI;
+	QMutex m_mutex;
+	SDRdaemonSinkSettings m_settings;
+	SDRdaemonSinkThread* m_sdrDaemonSinkThread;
+	QString m_deviceDescription;
+	std::time_t m_startingTimeStamp;
+	const QTimer& m_masterTimer;
+
+	void applySettings(const SDRdaemonSinkSettings& settings, bool force = false);
+};
+
+#endif // INCLUDE_SDRDAEMONSINKOUTPUT_H
diff --git a/plugins/samplesource/airspy/airspygui.cpp b/plugins/samplesource/airspy/airspygui.cpp
index 736fe10b9..882e0426f 100644
--- a/plugins/samplesource/airspy/airspygui.cpp
+++ b/plugins/samplesource/airspy/airspygui.cpp
@@ -35,6 +35,7 @@ AirspyGui::AirspyGui(DeviceUISet *deviceUISet, QWidget* parent) :
 	QWidget(parent),
 	ui(new Ui::AirspyGui),
 	m_deviceUISet(deviceUISet),
+	m_doApplySettings(true),
 	m_forceSettings(true),
 	m_settings(),
 	m_sampleSource(0),
@@ -116,9 +117,21 @@ bool AirspyGui::deserialize(const QByteArray& data)
 	}
 }
 
-bool AirspyGui::handleMessage(const Message& message __attribute__((unused)))
+bool AirspyGui::handleMessage(const Message& message)
 {
-    return false;
+    if (AirspyInput::MsgStartStop::match(message))
+    {
+        AirspyInput::MsgStartStop& notif = (AirspyInput::MsgStartStop&) message;
+        blockApplySettings(true);
+        ui->startStop->setChecked(notif.getStartStop());
+        blockApplySettings(false);
+
+        return true;
+    }
+    else
+    {
+        return false;
+    }
 }
 
 void AirspyGui::handleInputMessages()
@@ -340,18 +353,10 @@ void AirspyGui::on_vga_valueChanged(int value)
 
 void AirspyGui::on_startStop_toggled(bool checked)
 {
-    if (checked)
+    if (m_doApplySettings)
     {
-        if (m_deviceUISet->m_deviceSourceAPI->initAcquisition())
-        {
-            m_deviceUISet->m_deviceSourceAPI->startAcquisition();
-            DSPEngine::instance()->startAudioOutput();
-        }
-    }
-    else
-    {
-        m_deviceUISet->m_deviceSourceAPI->stopAcquisition();
-        DSPEngine::instance()->stopAudioOutput();
+        AirspyInput::MsgStartStop *message = AirspyInput::MsgStartStop::create(checked);
+        m_sampleSource->getInputMessageQueue()->push(message);
     }
 }
 
diff --git a/plugins/samplesource/airspy/airspygui.h b/plugins/samplesource/airspy/airspygui.h
index 563bf720b..2c3b77528 100644
--- a/plugins/samplesource/airspy/airspygui.h
+++ b/plugins/samplesource/airspy/airspygui.h
@@ -58,6 +58,7 @@ private:
 	Ui::AirspyGui* ui;
 
 	DeviceUISet* m_deviceUISet;
+	bool m_doApplySettings;
 	bool m_forceSettings;
 	AirspySettings m_settings;
 	QTimer m_updateTimer;
@@ -69,6 +70,7 @@ private:
     int m_lastEngineState;
     MessageQueue m_inputMessageQueue;
 
+    void blockApplySettings(bool block) { m_doApplySettings = !block; }
 	void displaySettings();
 	void displaySampleRates();
 	void sendSettings();
diff --git a/plugins/samplesource/airspy/airspyinput.cpp b/plugins/samplesource/airspy/airspyinput.cpp
index 8fa9943bd..b7fb98556 100644
--- a/plugins/samplesource/airspy/airspyinput.cpp
+++ b/plugins/samplesource/airspy/airspyinput.cpp
@@ -29,6 +29,7 @@
 #include "airspythread.h"
 
 MESSAGE_CLASS_DEFINITION(AirspyInput::MsgConfigureAirspy, Message)
+MESSAGE_CLASS_DEFINITION(AirspyInput::MsgStartStop, Message)
 MESSAGE_CLASS_DEFINITION(AirspyInput::MsgFileRecord, Message)
 
 const qint64 AirspyInput::loLowLimitFreq = 24000000L;
@@ -236,6 +237,27 @@ bool AirspyInput::handleMessage(const Message& message)
 
 		return true;
 	}
+    else if (MsgStartStop::match(message))
+    {
+        MsgStartStop& cmd = (MsgStartStop&) message;
+        qDebug() << "AirspyInput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");
+
+        if (cmd.getStartStop())
+        {
+            if (m_deviceAPI->initAcquisition())
+            {
+                m_deviceAPI->startAcquisition();
+                DSPEngine::instance()->startAudioOutput();
+            }
+        }
+        else
+        {
+            m_deviceAPI->stopAcquisition();
+            DSPEngine::instance()->stopAudioOutput();
+        }
+
+        return true;
+    }
     else if (MsgFileRecord::match(message))
     {
         MsgFileRecord& conf = (MsgFileRecord&) message;
diff --git a/plugins/samplesource/airspy/airspyinput.h b/plugins/samplesource/airspy/airspyinput.h
index 0692bd1f5..8ef9d7102 100644
--- a/plugins/samplesource/airspy/airspyinput.h
+++ b/plugins/samplesource/airspy/airspyinput.h
@@ -71,6 +71,25 @@ public:
         { }
     };
 
+    class MsgStartStop : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        bool getStartStop() const { return m_startStop; }
+
+        static MsgStartStop* create(bool startStop) {
+            return new MsgStartStop(startStop);
+        }
+
+    protected:
+        bool m_startStop;
+
+        MsgStartStop(bool startStop) :
+            Message(),
+            m_startStop(startStop)
+        { }
+    };
+
 	AirspyInput(DeviceSourceAPI *deviceAPI);
 	virtual ~AirspyInput();
 	virtual void destroy();
diff --git a/plugins/samplesource/fcdpro/fcdprogui.cpp b/plugins/samplesource/fcdpro/fcdprogui.cpp
index a905dd679..e3c4c7977 100644
--- a/plugins/samplesource/fcdpro/fcdprogui.cpp
+++ b/plugins/samplesource/fcdpro/fcdprogui.cpp
@@ -210,7 +210,19 @@ bool FCDProGui::deserialize(const QByteArray& data)
 
 bool FCDProGui::handleMessage(const Message& message __attribute__((unused)))
 {
-	return false;
+    if (BladerfInput::MsgStartStop::match(message))
+    {
+        BladerfInput::MsgStartStop& notif = (BladerfInput::MsgStartStop&) message;
+        blockApplySettings(true);
+        ui->startStop->setChecked(notif.getStartStop());
+        blockApplySettings(false);
+
+        return true;
+    }
+    else
+    {
+        return false;
+    }
 }
 
 void FCDProGui::handleInputMessages()
@@ -435,18 +447,10 @@ void FCDProGui::on_setDefaults_clicked(bool checked __attribute__((unused)))
 
 void FCDProGui::on_startStop_toggled(bool checked)
 {
-    if (checked)
+    if (m_doApplySettings)
     {
-        if (m_deviceUISet->m_deviceSourceAPI->initAcquisition())
-        {
-            m_deviceUISet->m_deviceSourceAPI->startAcquisition();
-            DSPEngine::instance()->startAudioOutput();
-        }
-    }
-    else
-    {
-        m_deviceUISet->m_deviceSourceAPI->stopAcquisition();
-        DSPEngine::instance()->stopAudioOutput();
+        BladerfInput::MsgStartStop *message = BladerfInput::MsgStartStop::create(checked);
+        m_sampleSource->getInputMessageQueue()->push(message);
     }
 }
 
diff --git a/plugins/samplesource/fcdpro/fcdprogui.h b/plugins/samplesource/fcdpro/fcdprogui.h
index 771c20b9e..de38ae1de 100644
--- a/plugins/samplesource/fcdpro/fcdprogui.h
+++ b/plugins/samplesource/fcdpro/fcdprogui.h
@@ -55,6 +55,7 @@ private:
 	Ui::FCDProGui* ui;
 
 	DeviceUISet* m_deviceUISet;
+	bool m_doApplySettings;
 	bool m_forceSettings;
 	FCDProSettings m_settings;
 	QTimer m_updateTimer;
@@ -66,6 +67,7 @@ private:
 	int m_lastEngineState;
 	MessageQueue m_inputMessageQueue;
 
+	void blockApplySettings(bool block) { m_doApplySettings = !block; }
 	void displaySettings();
 	void sendSettings();
 	void updateSampleRateAndFrequency();
diff --git a/plugins/samplesource/fcdpro/fcdproinput.cpp b/plugins/samplesource/fcdpro/fcdproinput.cpp
index 5665b721f..997b83da8 100644
--- a/plugins/samplesource/fcdpro/fcdproinput.cpp
+++ b/plugins/samplesource/fcdpro/fcdproinput.cpp
@@ -34,6 +34,7 @@
 #include "fcdproconst.h"
 
 MESSAGE_CLASS_DEFINITION(FCDProInput::MsgConfigureFCD, Message)
+MESSAGE_CLASS_DEFINITION(FCDProInput::MsgStartStop, Message)
 MESSAGE_CLASS_DEFINITION(FCDProInput::MsgFileRecord, Message)
 
 FCDProInput::FCDProInput(DeviceSourceAPI *deviceAPI) :
@@ -178,6 +179,27 @@ bool FCDProInput::handleMessage(const Message& message)
 		applySettings(conf.getSettings(), conf.getForce());
 		return true;
 	}
+    else if (MsgStartStop::match(message))
+    {
+        MsgStartStop& cmd = (MsgStartStop&) message;
+        qDebug() << "FCDProInput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");
+
+        if (cmd.getStartStop())
+        {
+            if (m_deviceAPI->initAcquisition())
+            {
+                m_deviceAPI->startAcquisition();
+                DSPEngine::instance()->startAudioOutput();
+            }
+        }
+        else
+        {
+            m_deviceAPI->stopAcquisition();
+            DSPEngine::instance()->stopAudioOutput();
+        }
+
+        return true;
+    }
     else if (MsgFileRecord::match(message))
     {
         MsgFileRecord& conf = (MsgFileRecord&) message;
diff --git a/plugins/samplesource/fcdpro/fcdproinput.h b/plugins/samplesource/fcdpro/fcdproinput.h
index c325c3b61..401643365 100644
--- a/plugins/samplesource/fcdpro/fcdproinput.h
+++ b/plugins/samplesource/fcdpro/fcdproinput.h
@@ -78,6 +78,25 @@ public:
         { }
     };
 
+    class MsgStartStop : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        bool getStartStop() const { return m_startStop; }
+
+        static MsgStartStop* create(bool startStop) {
+            return new MsgStartStop(startStop);
+        }
+
+    protected:
+        bool m_startStop;
+
+        MsgStartStop(bool startStop) :
+            Message(),
+            m_startStop(startStop)
+        { }
+    };
+
 	FCDProInput(DeviceSourceAPI *deviceAPI);
 	virtual ~FCDProInput();
 	virtual void destroy();
diff --git a/plugins/samplesource/fcdproplus/fcdproplusgui.cpp b/plugins/samplesource/fcdproplus/fcdproplusgui.cpp
index 76dd6458f..949fdd334 100644
--- a/plugins/samplesource/fcdproplus/fcdproplusgui.cpp
+++ b/plugins/samplesource/fcdproplus/fcdproplusgui.cpp
@@ -128,7 +128,19 @@ bool FCDProPlusGui::deserialize(const QByteArray& data)
 
 bool FCDProPlusGui::handleMessage(const Message& message __attribute__((unused)))
 {
-	return false;
+    if (FCDProPlusInput::MsgStartStop::match(message))
+    {
+        FCDProPlusInput::MsgStartStop& notif = (FCDProPlusInput::MsgStartStop&) message;
+        blockApplySettings(true);
+        ui->startStop->setChecked(notif.getStartStop());
+        blockApplySettings(false);
+
+        return true;
+    }
+    else
+    {
+        return false;
+    }
 }
 
 void FCDProPlusGui::handleInputMessages()
@@ -300,18 +312,10 @@ void FCDProPlusGui::on_ppm_valueChanged(int value)
 
 void FCDProPlusGui::on_startStop_toggled(bool checked)
 {
-    if (checked)
+    if (m_doApplySettings)
     {
-        if (m_deviceUISet->m_deviceSourceAPI->initAcquisition())
-        {
-            m_deviceUISet->m_deviceSourceAPI->startAcquisition();
-            DSPEngine::instance()->startAudioOutput();
-        }
-    }
-    else
-    {
-        m_deviceUISet->m_deviceSourceAPI->stopAcquisition();
-        DSPEngine::instance()->stopAudioOutput();
+        BladerfInput::MsgStartStop *message = BladerfInput::MsgStartStop::create(checked);
+        m_sampleSource->getInputMessageQueue()->push(message);
     }
 }
 
diff --git a/plugins/samplesource/fcdproplus/fcdproplusgui.h b/plugins/samplesource/fcdproplus/fcdproplusgui.h
index 70c566310..56be9dacd 100644
--- a/plugins/samplesource/fcdproplus/fcdproplusgui.h
+++ b/plugins/samplesource/fcdproplus/fcdproplusgui.h
@@ -54,6 +54,7 @@ private:
 	Ui::FCDProPlusGui* ui;
 
 	DeviceUISet* m_deviceUISet;
+	bool m_doApplySettings;
 	bool m_forceSettings;
 	FCDProPlusSettings m_settings;
 	QTimer m_updateTimer;
@@ -65,6 +66,7 @@ private:
 	int m_lastEngineState;
 	MessageQueue m_inputMessageQueue;
 
+	void blockApplySettings(bool block) { m_doApplySettings = !block; }
 	void displaySettings();
 	void sendSettings();
 	void updateSampleRateAndFrequency();
diff --git a/plugins/samplesource/fcdproplus/fcdproplusinput.cpp b/plugins/samplesource/fcdproplus/fcdproplusinput.cpp
index e5448404a..b54dd5f80 100644
--- a/plugins/samplesource/fcdproplus/fcdproplusinput.cpp
+++ b/plugins/samplesource/fcdproplus/fcdproplusinput.cpp
@@ -33,6 +33,7 @@
 #include "fcdproplusconst.h"
 
 MESSAGE_CLASS_DEFINITION(FCDProPlusInput::MsgConfigureFCD, Message)
+MESSAGE_CLASS_DEFINITION(FCDProPlusInput::MsgStartStop, Message)
 MESSAGE_CLASS_DEFINITION(FCDProPlusInput::MsgFileRecord, Message)
 
 FCDProPlusInput::FCDProPlusInput(DeviceSourceAPI *deviceAPI) :
@@ -172,6 +173,27 @@ bool FCDProPlusInput::handleMessage(const Message& message)
 		applySettings(conf.getSettings(), conf.getForce());
 		return true;
 	}
+    else if (MsgStartStop::match(message))
+    {
+        MsgStartStop& cmd = (MsgStartStop&) message;
+        qDebug() << "BladerfInput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");
+
+        if (cmd.getStartStop())
+        {
+            if (m_deviceAPI->initAcquisition())
+            {
+                m_deviceAPI->startAcquisition();
+                DSPEngine::instance()->startAudioOutput();
+            }
+        }
+        else
+        {
+            m_deviceAPI->stopAcquisition();
+            DSPEngine::instance()->stopAudioOutput();
+        }
+
+        return true;
+    }
     else if (MsgFileRecord::match(message))
     {
         MsgFileRecord& conf = (MsgFileRecord&) message;
diff --git a/plugins/samplesource/fcdproplus/fcdproplusinput.h b/plugins/samplesource/fcdproplus/fcdproplusinput.h
index ebbd7599d..9aa7ef3bc 100644
--- a/plugins/samplesource/fcdproplus/fcdproplusinput.h
+++ b/plugins/samplesource/fcdproplus/fcdproplusinput.h
@@ -58,6 +58,25 @@ public:
 		{ }
 	};
 
+    class MsgStartStop : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        bool getStartStop() const { return m_startStop; }
+
+        static MsgStartStop* create(bool startStop) {
+            return new MsgStartStop(startStop);
+        }
+
+    protected:
+        bool m_startStop;
+
+        MsgStartStop(bool startStop) :
+            Message(),
+            m_startStop(startStop)
+        { }
+    };
+
     class MsgFileRecord : public Message {
         MESSAGE_CLASS_DECLARATION
 
diff --git a/plugins/samplesource/filesource/filesourcegui.cpp b/plugins/samplesource/filesource/filesourcegui.cpp
index 8f157db36..af431da91 100644
--- a/plugins/samplesource/filesource/filesourcegui.cpp
+++ b/plugins/samplesource/filesource/filesourcegui.cpp
@@ -179,6 +179,15 @@ bool FileSourceGui::handleMessage(const Message& message)
 		updateWithStreamTime();
 		return true;
 	}
+	else if (FileSourceInput::MsgStartStop::match(message))
+    {
+	    FileSourceInput::MsgStartStop& notif = (FileSourceInput::MsgStartStop&) message;
+        blockApplySettings(true);
+        ui->startStop->setChecked(notif.getStartStop());
+        blockApplySettings(false);
+
+        return true;
+    }
 	else
 	{
 		return false;
@@ -207,18 +216,10 @@ void FileSourceGui::on_playLoop_toggled(bool checked __attribute__((unused)))
 
 void FileSourceGui::on_startStop_toggled(bool checked)
 {
-    if (checked)
+    if (m_doApplySettings)
     {
-        if (m_deviceUISet->m_deviceSourceAPI->initAcquisition())
-        {
-            m_deviceUISet->m_deviceSourceAPI->startAcquisition();
-            DSPEngine::instance()->startAudioOutput();
-        }
-    }
-    else
-    {
-        m_deviceUISet->m_deviceSourceAPI->stopAcquisition();
-        DSPEngine::instance()->stopAudioOutput();
+        FileSourceInput::MsgStartStop *message = FileSourceInput::MsgStartStop::create(checked);
+        m_sampleSource->getInputMessageQueue()->push(message);
     }
 }
 
diff --git a/plugins/samplesource/filesource/filesourcegui.h b/plugins/samplesource/filesource/filesourcegui.h
index c6a891fb1..ea03c168a 100644
--- a/plugins/samplesource/filesource/filesourcegui.h
+++ b/plugins/samplesource/filesource/filesourcegui.h
@@ -55,6 +55,7 @@ private:
 
 	DeviceUISet* m_deviceUISet;
 	FileSourceInput::Settings m_settings;
+	bool m_doApplySettings;
 	QTimer m_statusTimer;
 	std::vector<int> m_gains;
 	DeviceSampleSource* m_sampleSource;
@@ -72,6 +73,7 @@ private:
 	int m_lastEngineState;
 	MessageQueue m_inputMessageQueue;
 
+	void blockApplySettings(bool block) { m_doApplySettings = !block; }
 	void displaySettings();
 	void displayTime();
 	void sendSettings();
diff --git a/plugins/samplesource/filesource/filesourceinput.cpp b/plugins/samplesource/filesource/filesourceinput.cpp
index a724c2f5b..d4183117f 100644
--- a/plugins/samplesource/filesource/filesourceinput.cpp
+++ b/plugins/samplesource/filesource/filesourceinput.cpp
@@ -36,6 +36,7 @@ MESSAGE_CLASS_DEFINITION(FileSourceInput::MsgConfigureFileSourceName, Message)
 MESSAGE_CLASS_DEFINITION(FileSourceInput::MsgConfigureFileSourceWork, Message)
 MESSAGE_CLASS_DEFINITION(FileSourceInput::MsgConfigureFileSourceSeek, Message)
 MESSAGE_CLASS_DEFINITION(FileSourceInput::MsgConfigureFileSourceStreamTiming, Message)
+MESSAGE_CLASS_DEFINITION(FileSourceInput::MsgStartStop, Message)
 MESSAGE_CLASS_DEFINITION(FileSourceInput::MsgReportFileSourceAcquisition, Message)
 MESSAGE_CLASS_DEFINITION(FileSourceInput::MsgReportFileSourceStreamData, Message)
 MESSAGE_CLASS_DEFINITION(FileSourceInput::MsgReportFileSourceStreamTiming, Message)
@@ -288,6 +289,27 @@ bool FileSourceInput::handleMessage(const Message& message)
 
 		return true;
 	}
+    else if (MsgStartStop::match(message))
+    {
+        MsgStartStop& cmd = (MsgStartStop&) message;
+        qDebug() << "FileSourceInput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");
+
+        if (cmd.getStartStop())
+        {
+            if (m_deviceAPI->initAcquisition())
+            {
+                m_deviceAPI->startAcquisition();
+                DSPEngine::instance()->startAudioOutput();
+            }
+        }
+        else
+        {
+            m_deviceAPI->stopAcquisition();
+            DSPEngine::instance()->stopAudioOutput();
+        }
+
+        return true;
+    }
 	else
 	{
 		return false;
diff --git a/plugins/samplesource/filesource/filesourceinput.h b/plugins/samplesource/filesource/filesourceinput.h
index 20662e585..4abb37655 100644
--- a/plugins/samplesource/filesource/filesourceinput.h
+++ b/plugins/samplesource/filesource/filesourceinput.h
@@ -155,6 +155,25 @@ public:
 		{ }
 	};
 
+    class MsgStartStop : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        bool getStartStop() const { return m_startStop; }
+
+        static MsgStartStop* create(bool startStop) {
+            return new MsgStartStop(startStop);
+        }
+
+    protected:
+        bool m_startStop;
+
+        MsgStartStop(bool startStop) :
+            Message(),
+            m_startStop(startStop)
+        { }
+    };
+
 	class MsgReportFileSourceStreamData : public Message {
 		MESSAGE_CLASS_DECLARATION
 
diff --git a/plugins/samplesource/hackrfinput/hackrfinput.cpp b/plugins/samplesource/hackrfinput/hackrfinput.cpp
index cf4fa8b10..1ad13ef60 100644
--- a/plugins/samplesource/hackrfinput/hackrfinput.cpp
+++ b/plugins/samplesource/hackrfinput/hackrfinput.cpp
@@ -18,6 +18,7 @@
 
 #include <string.h>
 #include <errno.h>
+#include <unistd.h>
 #include <QDebug>
 
 #include "SWGDeviceSettings.h"
@@ -38,6 +39,7 @@
 MESSAGE_CLASS_DEFINITION(HackRFInput::MsgConfigureHackRF, Message)
 MESSAGE_CLASS_DEFINITION(HackRFInput::MsgReportHackRF, Message)
 MESSAGE_CLASS_DEFINITION(HackRFInput::MsgFileRecord, Message)
+MESSAGE_CLASS_DEFINITION(HackRFInput::MsgStartStop, Message)
 
 HackRFInput::HackRFInput(DeviceSourceAPI *deviceAPI) :
     m_deviceAPI(deviceAPI),
@@ -226,6 +228,27 @@ bool HackRFInput::handleMessage(const Message& message)
 
         return true;
     }
+    else if (MsgStartStop::match(message))
+    {
+        MsgStartStop& cmd = (MsgStartStop&) message;
+        qDebug() << "HackRFInput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");
+
+        if (cmd.getStartStop())
+        {
+            if (m_deviceAPI->initAcquisition())
+            {
+                m_deviceAPI->startAcquisition();
+                DSPEngine::instance()->startAudioOutput();
+            }
+        }
+        else
+        {
+            m_deviceAPI->stopAcquisition();
+            DSPEngine::instance()->stopAudioOutput();
+        }
+
+        return true;
+    }
 	else
 	{
 		return false;
@@ -502,19 +525,16 @@ int HackRFInput::webapiRun(
         SWGSDRangel::SWGDeviceState& response,
         QString& errorMessage __attribute__((unused)))
 {
-    if (run)
+    MsgStartStop *message = MsgStartStop::create(run);
+    m_inputMessageQueue.push(message);
+
+    if (m_guiMessageQueue) // forward to GUI if any
     {
-        if (m_deviceAPI->initAcquisition())
-        {
-            m_deviceAPI->startAcquisition();
-            DSPEngine::instance()->startAudioOutputImmediate();
-        }
-    }
-    else
-    {
-        m_deviceAPI->stopAcquisition();
+        MsgStartStop *msgToGUI = MsgStartStop::create(run);
+        m_guiMessageQueue->push(msgToGUI);
     }
 
+    usleep(100000);
     m_deviceAPI->getDeviceEngineStateStr(*response.getState());
     return 200;
 }
diff --git a/plugins/samplesource/hackrfinput/hackrfinput.h b/plugins/samplesource/hackrfinput/hackrfinput.h
index 29a6654f0..1fe08c1a0 100644
--- a/plugins/samplesource/hackrfinput/hackrfinput.h
+++ b/plugins/samplesource/hackrfinput/hackrfinput.h
@@ -72,6 +72,25 @@ public:
 		{ }
 	};
 
+    class MsgStartStop : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        bool getStartStop() const { return m_startStop; }
+
+        static MsgStartStop* create(bool startStop) {
+            return new MsgStartStop(startStop);
+        }
+
+    protected:
+        bool m_startStop;
+
+        MsgStartStop(bool startStop) :
+            Message(),
+            m_startStop(startStop)
+        { }
+    };
+
     class MsgFileRecord : public Message {
         MESSAGE_CLASS_DECLARATION
 
diff --git a/plugins/samplesource/hackrfinput/hackrfinputgui.cpp b/plugins/samplesource/hackrfinput/hackrfinputgui.cpp
index fc1a89b34..1f227cefd 100644
--- a/plugins/samplesource/hackrfinput/hackrfinputgui.cpp
+++ b/plugins/samplesource/hackrfinput/hackrfinputgui.cpp
@@ -130,6 +130,15 @@ bool HackRFInputGui::handleMessage(const Message& message)
         displaySettings();
         return true;
     }
+    else if (HackRFInput::MsgStartStop::match(message))
+    {
+        HackRFInput::MsgStartStop& notif = (HackRFInput::MsgStartStop&) message;
+        blockApplySettings(true);
+        ui->startStop->setChecked(notif.getStartStop());
+        blockApplySettings(false);
+
+        return true;
+    }
     else
     {
         return false;
@@ -333,25 +342,10 @@ void HackRFInputGui::on_vga_valueChanged(int value)
 
 void HackRFInputGui::on_startStop_toggled(bool checked)
 {
-    if (checked)
+    if (m_doApplySettings)
     {
-        // forcibly stop the Tx if present before starting
-        if (m_deviceUISet->m_deviceSourceAPI->getSinkBuddies().size() > 0)
-        {
-            DeviceSinkAPI *buddy = m_deviceUISet->m_deviceSourceAPI->getSinkBuddies()[0];
-            buddy->stopGeneration();
-        }
-
-        if (m_deviceUISet->m_deviceSourceAPI->initAcquisition())
-        {
-            m_deviceUISet->m_deviceSourceAPI->startAcquisition();
-            DSPEngine::instance()->startAudioOutput();
-        }
-    }
-    else
-    {
-        m_deviceUISet->m_deviceSourceAPI->stopAcquisition();
-        DSPEngine::instance()->stopAudioOutput();
+        HackRFInput::MsgStartStop *message = HackRFInput::MsgStartStop::create(checked);
+        m_sampleSource->getInputMessageQueue()->push(message);
     }
 }
 
diff --git a/plugins/samplesource/limesdrinput/limesdrinput.cpp b/plugins/samplesource/limesdrinput/limesdrinput.cpp
index d2ffdc771..d8809076f 100644
--- a/plugins/samplesource/limesdrinput/limesdrinput.cpp
+++ b/plugins/samplesource/limesdrinput/limesdrinput.cpp
@@ -18,6 +18,7 @@
 #include <QDebug>
 #include <cstddef>
 #include <string.h>
+#include <unistd.h>
 #include "lime/LimeSuite.h"
 
 #include "SWGDeviceSettings.h"
@@ -40,6 +41,7 @@ MESSAGE_CLASS_DEFINITION(LimeSDRInput::MsgGetStreamInfo, Message)
 MESSAGE_CLASS_DEFINITION(LimeSDRInput::MsgGetDeviceInfo, Message)
 MESSAGE_CLASS_DEFINITION(LimeSDRInput::MsgReportStreamInfo, Message)
 MESSAGE_CLASS_DEFINITION(LimeSDRInput::MsgFileRecord, Message)
+MESSAGE_CLASS_DEFINITION(LimeSDRInput::MsgStartStop, Message)
 
 LimeSDRInput::LimeSDRInput(DeviceSourceAPI *deviceAPI) :
     m_deviceAPI(deviceAPI),
@@ -660,6 +662,27 @@ bool LimeSDRInput::handleMessage(const Message& message)
 
         return true;
     }
+    else if (MsgStartStop::match(message))
+    {
+        MsgStartStop& cmd = (MsgStartStop&) message;
+        qDebug() << "LimeSDRInput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");
+
+        if (cmd.getStartStop())
+        {
+            if (m_deviceAPI->initAcquisition())
+            {
+                m_deviceAPI->startAcquisition();
+                DSPEngine::instance()->startAudioOutput();
+            }
+        }
+        else
+        {
+            m_deviceAPI->stopAcquisition();
+            DSPEngine::instance()->stopAudioOutput();
+        }
+
+        return true;
+    }
     else
     {
         return false;
@@ -1258,19 +1281,16 @@ int LimeSDRInput::webapiRun(
         SWGSDRangel::SWGDeviceState& response,
         QString& errorMessage __attribute__((unused)))
 {
-    if (run)
+    MsgStartStop *message = MsgStartStop::create(run);
+    m_inputMessageQueue.push(message);
+
+    if (m_guiMessageQueue) // forward to GUI if any
     {
-        if (m_deviceAPI->initAcquisition())
-        {
-            m_deviceAPI->startAcquisition();
-            DSPEngine::instance()->startAudioOutputImmediate();
-        }
-    }
-    else
-    {
-        m_deviceAPI->stopAcquisition();
+        MsgStartStop *msgToGUI = MsgStartStop::create(run);
+        m_guiMessageQueue->push(msgToGUI);
     }
 
+    usleep(100000);
     m_deviceAPI->getDeviceEngineStateStr(*response.getState());
     return 200;
 }
diff --git a/plugins/samplesource/limesdrinput/limesdrinput.h b/plugins/samplesource/limesdrinput/limesdrinput.h
index 967b8df15..927280f8b 100644
--- a/plugins/samplesource/limesdrinput/limesdrinput.h
+++ b/plugins/samplesource/limesdrinput/limesdrinput.h
@@ -185,6 +185,25 @@ public:
         { }
     };
 
+    class MsgStartStop : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        bool getStartStop() const { return m_startStop; }
+
+        static MsgStartStop* create(bool startStop) {
+            return new MsgStartStop(startStop);
+        }
+
+    protected:
+        bool m_startStop;
+
+        MsgStartStop(bool startStop) :
+            Message(),
+            m_startStop(startStop)
+        { }
+    };
+
     LimeSDRInput(DeviceSourceAPI *deviceAPI);
     virtual ~LimeSDRInput();
     virtual void destroy();
diff --git a/plugins/samplesource/limesdrinput/limesdrinputgui.cpp b/plugins/samplesource/limesdrinput/limesdrinputgui.cpp
index 353ef6d38..eea841714 100644
--- a/plugins/samplesource/limesdrinput/limesdrinputgui.cpp
+++ b/plugins/samplesource/limesdrinput/limesdrinputgui.cpp
@@ -219,8 +219,19 @@ bool LimeSDRInputGUI::handleMessage(const Message& message)
         ui->temperatureText->setText(tr("%1C").arg(QString::number(report.getTemperature(), 'f', 0)));
         return true;
     }
+    else if (LimeSDRInput::MsgStartStop::match(message))
+    {
+        LimeSDRInput::MsgStartStop& notif = (LimeSDRInput::MsgStartStop&) message;
+        blockApplySettings(true);
+        ui->startStop->setChecked(notif.getStartStop());
+        blockApplySettings(false);
 
-    return false;
+        return true;
+    }
+    else
+    {
+        return false;
+    }
 }
 
 void LimeSDRInputGUI::handleInputMessages()
@@ -415,18 +426,10 @@ void LimeSDRInputGUI::blockApplySettings(bool block)
 
 void LimeSDRInputGUI::on_startStop_toggled(bool checked)
 {
-    if (checked)
+    if (m_doApplySettings)
     {
-        if (m_deviceUISet->m_deviceSourceAPI->initAcquisition())
-        {
-            m_deviceUISet->m_deviceSourceAPI->startAcquisition();
-            DSPEngine::instance()->startAudioOutput();
-        }
-    }
-    else
-    {
-        m_deviceUISet->m_deviceSourceAPI->stopAcquisition();
-        DSPEngine::instance()->stopAudioOutput();
+        LimeSDRInput::MsgStartStop *message = LimeSDRInput::MsgStartStop::create(checked);
+        m_limeSDRInput->getInputMessageQueue()->push(message);
     }
 }
 
diff --git a/plugins/samplesource/plutosdrinput/plutosdrinput.cpp b/plugins/samplesource/plutosdrinput/plutosdrinput.cpp
index c0e90cf59..a00125204 100644
--- a/plugins/samplesource/plutosdrinput/plutosdrinput.cpp
+++ b/plugins/samplesource/plutosdrinput/plutosdrinput.cpp
@@ -15,6 +15,7 @@
 ///////////////////////////////////////////////////////////////////////////////////
 
 #include <QDebug>
+#include <unistd.h>
 
 #include "SWGDeviceSettings.h"
 #include "SWGDeviceState.h"
@@ -34,6 +35,7 @@
 
 MESSAGE_CLASS_DEFINITION(PlutoSDRInput::MsgConfigurePlutoSDR, Message)
 MESSAGE_CLASS_DEFINITION(PlutoSDRInput::MsgFileRecord, Message)
+MESSAGE_CLASS_DEFINITION(PlutoSDRInput::MsgStartStop, Message)
 
 PlutoSDRInput::PlutoSDRInput(DeviceSourceAPI *deviceAPI) :
     m_deviceAPI(deviceAPI),
@@ -154,6 +156,27 @@ bool PlutoSDRInput::handleMessage(const Message& message)
 
         return true;
     }
+    else if (MsgStartStop::match(message))
+    {
+        MsgStartStop& cmd = (MsgStartStop&) message;
+        qDebug() << "PlutoSDRInput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");
+
+        if (cmd.getStartStop())
+        {
+            if (m_deviceAPI->initAcquisition())
+            {
+                m_deviceAPI->startAcquisition();
+                DSPEngine::instance()->startAudioOutput();
+            }
+        }
+        else
+        {
+            m_deviceAPI->stopAcquisition();
+            DSPEngine::instance()->stopAudioOutput();
+        }
+
+        return true;
+    }
     else if (DevicePlutoSDRShared::MsgCrossReportToBuddy::match(message)) // message from buddy
     {
         DevicePlutoSDRShared::MsgCrossReportToBuddy& conf = (DevicePlutoSDRShared::MsgCrossReportToBuddy&) message;
@@ -578,19 +601,16 @@ int PlutoSDRInput::webapiRun(
         SWGSDRangel::SWGDeviceState& response,
         QString& errorMessage __attribute__((unused)))
 {
-    if (run)
+    MsgStartStop *message = MsgStartStop::create(run);
+    m_inputMessageQueue.push(message);
+
+    if (m_guiMessageQueue) // forward to GUI if any
     {
-        if (m_deviceAPI->initAcquisition())
-        {
-            m_deviceAPI->startAcquisition();
-            DSPEngine::instance()->startAudioOutputImmediate();
-        }
-    }
-    else
-    {
-        m_deviceAPI->stopAcquisition();
+        MsgStartStop *msgToGUI = MsgStartStop::create(run);
+        m_guiMessageQueue->push(msgToGUI);
     }
 
+    usleep(100000);
     m_deviceAPI->getDeviceEngineStateStr(*response.getState());
     return 200;
 }
diff --git a/plugins/samplesource/plutosdrinput/plutosdrinput.h b/plugins/samplesource/plutosdrinput/plutosdrinput.h
index 7b33ca3d8..b1132a5cd 100644
--- a/plugins/samplesource/plutosdrinput/plutosdrinput.h
+++ b/plugins/samplesource/plutosdrinput/plutosdrinput.h
@@ -73,6 +73,24 @@ public:
         { }
     };
 
+    class MsgStartStop : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        bool getStartStop() const { return m_startStop; }
+
+        static MsgStartStop* create(bool startStop) {
+            return new MsgStartStop(startStop);
+        }
+
+    protected:
+        bool m_startStop;
+
+        MsgStartStop(bool startStop) :
+            Message(),
+            m_startStop(startStop)
+        { }
+    };
 
     PlutoSDRInput(DeviceSourceAPI *deviceAPI);
     ~PlutoSDRInput();
diff --git a/plugins/samplesource/plutosdrinput/plutosdrinputgui.cpp b/plugins/samplesource/plutosdrinput/plutosdrinputgui.cpp
index bc404d9a0..8919a423f 100644
--- a/plugins/samplesource/plutosdrinput/plutosdrinputgui.cpp
+++ b/plugins/samplesource/plutosdrinput/plutosdrinputgui.cpp
@@ -131,7 +131,16 @@ bool PlutoSDRInputGui::deserialize(const QByteArray& data)
 
 bool PlutoSDRInputGui::handleMessage(const Message& message __attribute__((unused)))
 {
-    if (DevicePlutoSDRShared::MsgCrossReportToBuddy::match(message)) // message from buddy
+    if (PlutoSDRInput::MsgStartStop::match(message))
+    {
+        PlutoSDRInput::MsgStartStop& notif = (PlutoSDRInput::MsgStartStop&) message;
+        blockApplySettings(true);
+        ui->startStop->setChecked(notif.getStartStop());
+        blockApplySettings(false);
+
+        return true;
+    }
+    else if (DevicePlutoSDRShared::MsgCrossReportToBuddy::match(message)) // message from buddy
     {
         DevicePlutoSDRShared::MsgCrossReportToBuddy& conf = (DevicePlutoSDRShared::MsgCrossReportToBuddy&) message;
         m_settings.m_devSampleRate = conf.getDevSampleRate();
@@ -153,18 +162,10 @@ bool PlutoSDRInputGui::handleMessage(const Message& message __attribute__((unuse
 
 void PlutoSDRInputGui::on_startStop_toggled(bool checked)
 {
-    if (checked)
+    if (m_doApplySettings)
     {
-        if (m_deviceUISet->m_deviceSourceAPI->initAcquisition())
-        {
-            m_deviceUISet->m_deviceSourceAPI->startAcquisition();
-            DSPEngine::instance()->startAudioOutput();
-        }
-    }
-    else
-    {
-        m_deviceUISet->m_deviceSourceAPI->stopAcquisition();
-        DSPEngine::instance()->stopAudioOutput();
+        PlutoSDRInput::MsgStartStop *message = PlutoSDRInput::MsgStartStop::create(checked);
+        m_sampleSource->getInputMessageQueue()->push(message);
     }
 }
 
diff --git a/plugins/samplesource/rtlsdr/rtlsdrgui.cpp b/plugins/samplesource/rtlsdr/rtlsdrgui.cpp
index 7eb93a755..c200fbac6 100644
--- a/plugins/samplesource/rtlsdr/rtlsdrgui.cpp
+++ b/plugins/samplesource/rtlsdr/rtlsdrgui.cpp
@@ -149,6 +149,15 @@ bool RTLSDRGui::handleMessage(const Message& message)
 	    blockApplySettings(false);
 	    return true;
 	}
+    if (RTLSDRInput::MsgStartStop::match(message))
+    {
+        RTLSDRInput::MsgStartStop& notif = (RTLSDRInput::MsgStartStop&) message;
+        blockApplySettings(true);
+        ui->startStop->setChecked(notif.getStartStop());
+        blockApplySettings(false);
+
+        return true;
+    }
 	else
 	{
 		return false;
@@ -320,18 +329,10 @@ void RTLSDRGui::on_gain_valueChanged(int value)
 
 void RTLSDRGui::on_startStop_toggled(bool checked)
 {
-    if (checked)
+    if (m_doApplySettings)
     {
-        if (m_deviceUISet->m_deviceSourceAPI->initAcquisition())
-        {
-            m_deviceUISet->m_deviceSourceAPI->startAcquisition();
-            DSPEngine::instance()->startAudioOutput();
-        }
-    }
-    else
-    {
-        m_deviceUISet->m_deviceSourceAPI->stopAcquisition();
-        DSPEngine::instance()->stopAudioOutput();
+        RTLSDRInput::MsgStartStop *message = RTLSDRInput::MsgStartStop::create(checked);
+        m_sampleSource->getInputMessageQueue()->push(message);
     }
 }
 
diff --git a/plugins/samplesource/rtlsdr/rtlsdrinput.cpp b/plugins/samplesource/rtlsdr/rtlsdrinput.cpp
index a691e96bc..bc1c52978 100644
--- a/plugins/samplesource/rtlsdr/rtlsdrinput.cpp
+++ b/plugins/samplesource/rtlsdr/rtlsdrinput.cpp
@@ -18,6 +18,7 @@
 #include <QDebug>
 #include <string.h>
 #include <errno.h>
+#include <unistd.h>
 
 #include "SWGDeviceSettings.h"
 #include "SWGRtlSdrSettings.h"
@@ -34,6 +35,7 @@
 MESSAGE_CLASS_DEFINITION(RTLSDRInput::MsgConfigureRTLSDR, Message)
 MESSAGE_CLASS_DEFINITION(RTLSDRInput::MsgReportRTLSDR, Message)
 MESSAGE_CLASS_DEFINITION(RTLSDRInput::MsgFileRecord, Message)
+MESSAGE_CLASS_DEFINITION(RTLSDRInput::MsgStartStop, Message)
 
 const quint64 RTLSDRInput::frequencyLowRangeMin = 1000UL;
 const quint64 RTLSDRInput::frequencyLowRangeMax = 275000UL;
@@ -274,6 +276,27 @@ bool RTLSDRInput::handleMessage(const Message& message)
 
         return true;
     }
+    else if (MsgStartStop::match(message))
+    {
+        MsgStartStop& cmd = (MsgStartStop&) message;
+        qDebug() << "RTLSDRInput::handleMessage: MsgStartStop: " << (cmd.getStartStop() ? "start" : "stop");
+
+        if (cmd.getStartStop())
+        {
+            if (m_deviceAPI->initAcquisition())
+            {
+                m_deviceAPI->startAcquisition();
+                DSPEngine::instance()->startAudioOutput();
+            }
+        }
+        else
+        {
+            m_deviceAPI->stopAcquisition();
+            DSPEngine::instance()->stopAudioOutput();
+        }
+
+        return true;
+    }
     else
     {
         return false;
@@ -541,19 +564,16 @@ int RTLSDRInput::webapiRun(
         SWGSDRangel::SWGDeviceState& response,
         QString& errorMessage __attribute__((unused)))
 {
-    if (run)
+    MsgStartStop *message = MsgStartStop::create(run);
+    m_inputMessageQueue.push(message);
+
+    if (m_guiMessageQueue) // forward to GUI if any
     {
-        if (m_deviceAPI->initAcquisition())
-        {
-            m_deviceAPI->startAcquisition();
-            DSPEngine::instance()->startAudioOutputImmediate();
-        }
-    }
-    else
-    {
-        m_deviceAPI->stopAcquisition();
+        MsgStartStop *msgToGUI = MsgStartStop::create(run);
+        m_guiMessageQueue->push(msgToGUI);
     }
 
+    usleep(100000);
     m_deviceAPI->getDeviceEngineStateStr(*response.getState());
     return 200;
 }
diff --git a/plugins/samplesource/rtlsdr/rtlsdrinput.h b/plugins/samplesource/rtlsdr/rtlsdrinput.h
index 23ad90866..7b6b7c911 100644
--- a/plugins/samplesource/rtlsdr/rtlsdrinput.h
+++ b/plugins/samplesource/rtlsdr/rtlsdrinput.h
@@ -92,6 +92,25 @@ public:
         { }
     };
 
+    class MsgStartStop : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        bool getStartStop() const { return m_startStop; }
+
+        static MsgStartStop* create(bool startStop) {
+            return new MsgStartStop(startStop);
+        }
+
+    protected:
+        bool m_startStop;
+
+        MsgStartStop(bool startStop) :
+            Message(),
+            m_startStop(startStop)
+        { }
+    };
+
 	RTLSDRInput(DeviceSourceAPI *deviceAPI);
 	virtual ~RTLSDRInput();
 	virtual void destroy();