diff --git a/htdocs/telephonie/script/retour-traitement.php b/htdocs/telephonie/script/retour-traitement.php
index 129aa6634f9..5af0c7c155d 100644
--- a/htdocs/telephonie/script/retour-traitement.php
+++ b/htdocs/telephonie/script/retour-traitement.php
@@ -233,4 +233,8 @@ for ($i = 0 ; $i < $n ; $i++)
        *
        */
     }
+  else
+    {
+      print "Ligne inconnue : $numero\n";
+    }
 }