diff --git a/TBF/Rig/DataEntry/S620/FormForMechanicalMeters.cs b/TBF/Rig/DataEntry/S620/FormForMechanicalMeters.cs
index 8a3960514..afd699071 100644
--- a/TBF/Rig/DataEntry/S620/FormForMechanicalMeters.cs
+++ b/TBF/Rig/DataEntry/S620/FormForMechanicalMeters.cs
@@ -488,6 +488,13 @@ namespace TBF.Rig.DataEntry.S620
         /// <param name="currentFocusOwner">TextBox control which received the event</param>
         private void ProcKeyPress(object sender, KeyPressEventArgs e, ComboBox currentFocusOwner)
         {
+            if (e.KeyChar == 'ľ' || e.KeyChar == 'š' || e.KeyChar == 'č' || e.KeyChar == 'ť' || e.KeyChar == 'ž' || e.KeyChar == 'ý' || e.KeyChar == 'á' || e.KeyChar == 'í' || e.KeyChar == 'é')
+            {
+                MessageBox.Show("Zlá klávesnica !!!");
+                e.Handled = true;
+                return;
+            }
+
             if (e.KeyChar == '+')
             {
                 /// Process '+' key ..... Form completed
diff --git a/TBF/Rig/DataEntry/S620/FormForMechanicalMetersWithTracing.cs b/TBF/Rig/DataEntry/S620/FormForMechanicalMetersWithTracing.cs
index 0a31374f2..0c57dad01 100644
--- a/TBF/Rig/DataEntry/S620/FormForMechanicalMetersWithTracing.cs
+++ b/TBF/Rig/DataEntry/S620/FormForMechanicalMetersWithTracing.cs
@@ -859,6 +859,13 @@ namespace TBF.Rig.DataEntry.S620
 		/// <param name="currentFocusOwner">TextBox control which received the event</param>
 		private void BodyNoTextBoxKeyPress(object sender, KeyPressEventArgs e, int wmNr0)
         {
+            if (e.KeyChar == 'ľ' || e.KeyChar == 'š' || e.KeyChar == 'č' || e.KeyChar == 'ť' || e.KeyChar == 'ž' || e.KeyChar == 'ý' || e.KeyChar == 'á' || e.KeyChar == 'í' || e.KeyChar == 'é')
+            {
+                MessageBox.Show("Zlá klávesnica !!!");
+                e.Handled = true;
+                return;
+            }
+
             if (closeButton != '\0' && e.KeyChar == closeButton)
 			{
 				/// Process '+' key ..... Form completed