diff --git a/fhem/fhem.pl b/fhem/fhem.pl
index 4405b67ec..71475aac4 100755
--- a/fhem/fhem.pl
+++ b/fhem/fhem.pl
@@ -65,7 +65,7 @@ sub GlobalAttr($$$$);
 sub HandleArchiving($;$);
 sub HandleTimeout();
 sub IOWrite($@);
-sub InternalTimer($$$$);
+sub InternalTimer($$$;$);
 sub InternalVal($$$);
 sub IsDisabled($);
 sub IsDummy($);