diff --git a/Configuration.cpp b/Configuration.cpp
index 3954160b1..90bdb462b 100644
--- a/Configuration.cpp
+++ b/Configuration.cpp
@@ -245,6 +245,7 @@ namespace
           |X85|X86|X87|X88|X89|X90|X91
           |X92|X93|X94|X95|X96|X97|X98
           |X99
+          |[0-9][0-9][0-9][0-9]            # 4-digit numbers
         )
       )", QRegularExpression::CaseInsensitiveOption | QRegularExpression::ExtendedPatternSyntaxOption};
 
diff --git a/widgets/mainwindow.cpp b/widgets/mainwindow.cpp
index 783afb7fe..2093fa3e8 100644
--- a/widgets/mainwindow.cpp
+++ b/widgets/mainwindow.cpp
@@ -6102,6 +6102,9 @@ void MainWindow::genStdMsgs(QString rpt, bool unconditional)
           t1 = t1.asprintf("%4.4d",ui->sbSerialNumber->value());
           sent=rst + t1;
         }
+        if(t1.contains(QRegularExpression {"\\d\\d\\d\\d"})) {
+          t1 = m_config.RTTY_Exchange();
+        }
       }
       if(SpecOp::EU_VHF==m_specOp) {
         QString a;