diff --git a/Documentation/UserManual/ProgrammingGuide.pdf b/Documentation/UserManual/ProgrammingGuide.pdf
index a06fe98..9d2243e 100644
Binary files a/Documentation/UserManual/ProgrammingGuide.pdf and b/Documentation/UserManual/ProgrammingGuide.pdf differ
diff --git a/Documentation/UserManual/ProgrammingGuide.tex b/Documentation/UserManual/ProgrammingGuide.tex
index b46d877..a1dafed 100644
--- a/Documentation/UserManual/ProgrammingGuide.tex
+++ b/Documentation/UserManual/ProgrammingGuide.tex
@@ -212,7 +212,11 @@ VNA:FREQ:SPAN? # Read the current span
 \section{Commands}
 \subsection{General Commands}
 \subsubsection{*IDN}
-\query{Returns the identifications string}{*IDN?}{None}{LibreVNA,LibreVNA-GUI,dummy\_serial,<software version>}
+\query{Returns the identifications string}{*IDN?}{None}{LibreVNA,LibreVNA-GUI,<serial>,<software version>}
+\begin{itemize}
+\item The serial number is the serial number from the connected LibreVNA. If none is connected, it will be set to ``Not connected''
+\item The software version is the version of the \gui{}, not the firmware version of the connected \vna{}
+\end{itemize}
 \subsubsection{*RST}
 \event{Resets the GUI (and any connected device) to the default state}{*RST}{None}
 \subsubsection{*CLS}
diff --git a/Software/PC_Application/LibreVNA-GUI/appwindow.cpp b/Software/PC_Application/LibreVNA-GUI/appwindow.cpp
index b02e749..efb8bae 100644
--- a/Software/PC_Application/LibreVNA-GUI/appwindow.cpp
+++ b/Software/PC_Application/LibreVNA-GUI/appwindow.cpp
@@ -516,7 +516,14 @@ void AppWindow::CreateToolbars()
 void AppWindow::SetupSCPI()
 {
     scpi.add(new SCPICommand("*IDN", nullptr, [=](QStringList){
-        return "LibreVNA,LibreVNA-GUI,dummy_serial,"+appVersion;
+        QString ret = "LibreVNA,LibreVNA-GUI,";
+        if(device) {
+            ret += device->getSerial();
+        } else {
+            ret += "Not connected";
+        }
+        ret += ","+appVersion;
+        return ret;
     }));
     scpi.add(new SCPICommand("*RST", [=](QStringList){
         SetResetState();