diff --git a/commandwidget.cpp b/commandwidget.cpp
--- a/commandwidget.cpp
+++ b/commandwidget.cpp
@@ -77,6 +77,16 @@ void CommandWidget::onSendClicked()
 void CommandWidget::onASCIIToggled(bool checked)
 {
     ui->leCommand->setMode(checked);
+    if (checked)
+    {
+        storedHexText = ui->leCommand->text();
+        ui->leCommand->setText(storedAsciiText);
+    }
+    else
+    {
+        storedAsciiText = ui->leCommand->text();
+        ui->leCommand->setText(storedHexText);
+    }
 }
 
 bool CommandWidget::isASCIIMode()