diff --git a/Software/PC_Application/LibreVNA-GUI/appwindow.cpp b/Software/PC_Application/LibreVNA-GUI/appwindow.cpp
index 487fcf7..79301a6 100644
--- a/Software/PC_Application/LibreVNA-GUI/appwindow.cpp
+++ b/Software/PC_Application/LibreVNA-GUI/appwindow.cpp
@@ -143,11 +143,6 @@ AppWindow::AppWindow(QWidget *parent)
     central = new QStackedWidget;
     setCentralWidget(central);
 
-    auto vnaIndex = modeHandler->createMode("Vector Network Analyzer", Mode::Type::VNA);
-    modeHandler->createMode("Signal Generator", Mode::Type::SG);
-    modeHandler->createMode("Spectrum Analyzer", Mode::Type::SA);
-    modeHandler->setCurrentIndex(vnaIndex);
-
     auto setModeStatusbar = [=](const QString &msg) {
         lModeInfo.setText(msg);
     };
@@ -170,10 +165,9 @@ AppWindow::AppWindow(QWidget *parent)
 
     SetupSCPI();
 
+    SetInitialState();
+
     auto& pref = Preferences::getInstance();
-    if(pref.Startup.UseSetupFile) {
-        LoadSetup(pref.Startup.SetupFile);
-    }
     // List available devices
     UpdateDeviceList();
     if(pref.Startup.ConnectToFirstDevice && deviceList.size() > 0) {
@@ -315,6 +309,21 @@ void AppWindow::closeEvent(QCloseEvent *event)
     QMainWindow::closeEvent(event);
 }
 
+void AppWindow::SetInitialState()
+{
+    modeHandler->closeModes();
+
+    auto& pref = Preferences::getInstance();
+    if(pref.Startup.UseSetupFile) {
+        LoadSetup(pref.Startup.SetupFile);
+    } else {
+        auto vnaIndex = modeHandler->createMode("Vector Network Analyzer", Mode::Type::VNA);
+        modeHandler->createMode("Signal Generator", Mode::Type::SG);
+        modeHandler->createMode("Spectrum Analyzer", Mode::Type::SA);
+        modeHandler->setCurrentIndex(vnaIndex);
+    }
+}
+
 bool AppWindow::ConnectToDevice(QString serial, DeviceDriver *driver)
 {
     if(serial.isEmpty()) {
@@ -477,6 +486,10 @@ void AppWindow::SetupSCPI()
     scpi.add(new SCPICommand("*IDN", nullptr, [=](QStringList){
         return "LibreVNA,LibreVNA-GUI,dummy_serial,"+appVersion;
     }));
+    scpi.add(new SCPICommand("*RST", [=](QStringList){
+        SetInitialState();
+        return SCPI::getResultName(SCPI::Result::Empty);
+    }, nullptr));
     scpi.add(new SCPICommand("*OPC", nullptr, [=](QStringList){
         return "1";
     }));
diff --git a/Software/PC_Application/LibreVNA-GUI/appwindow.h b/Software/PC_Application/LibreVNA-GUI/appwindow.h
index e47376e..175dd1b 100644
--- a/Software/PC_Application/LibreVNA-GUI/appwindow.h
+++ b/Software/PC_Application/LibreVNA-GUI/appwindow.h
@@ -58,6 +58,7 @@ public slots:
 protected:
     void closeEvent(QCloseEvent *event) override;
 private slots:
+    void SetInitialState();
     bool ConnectToDevice(QString serial = QString(), DeviceDriver *driver = nullptr);
     void DisconnectDevice();
     int UpdateDeviceList();
diff --git a/Software/PC_Application/LibreVNA-GUI/scpi.cpp b/Software/PC_Application/LibreVNA-GUI/scpi.cpp
index 4684033..6b5a89b 100644
--- a/Software/PC_Application/LibreVNA-GUI/scpi.cpp
+++ b/Software/PC_Application/LibreVNA-GUI/scpi.cpp
@@ -5,7 +5,6 @@
 SCPI::SCPI() :
     SCPINode("")
 {
-    lastNode = this;
     add(new SCPICommand("*LST", nullptr, [=](QStringList){
         QString list;
         createCommandList("", list);
@@ -97,16 +96,19 @@ QString SCPI::getResultName(SCPI::Result r)
 void SCPI::input(QString line)
 {
     auto cmds = line.split(";");
+    SCPINode *lastNode = this;
     for(auto cmd : cmds) {
-        if(cmd[0] == ':' || cmd[0] == '*') {
-            // reset to root node
-            lastNode = this;
+        if(cmd.size() > 0) {
+            if(cmd[0] == ':' || cmd[0] == '*') {
+                // reset to root node
+                lastNode = this;
+            }
+            if(cmd[0] == ':') {
+                cmd.remove(0, 1);
+            }
+            auto response = lastNode->parse(cmd, lastNode);
+            emit output(response);
         }
-        if(cmd[0] == ':') {
-            cmd.remove(0, 1);
-        }
-        auto response = lastNode->parse(cmd, lastNode);
-        emit output(response);
     }
 }
 
diff --git a/Software/PC_Application/LibreVNA-GUI/scpi.h b/Software/PC_Application/LibreVNA-GUI/scpi.h
index f56f92e..10634cf 100644
--- a/Software/PC_Application/LibreVNA-GUI/scpi.h
+++ b/Software/PC_Application/LibreVNA-GUI/scpi.h
@@ -81,9 +81,6 @@ public slots:
     void input(QString line);
 signals:
     void output(QString line);
-
-private:
-    SCPINode *lastNode;
 };
 
 #endif // SCPI_H