diff --git a/mixer/src/Module.C b/mixer/src/Module.C
index 8a953a3..9268bff 100644
--- a/mixer/src/Module.C
+++ b/mixer/src/Module.C
@@ -234,7 +234,10 @@ Module::handle_control_changed ( Port *p )
 bool
 Module::Port::connected_osc ( void ) const
 {
-    return _scaled_signal->connected();
+    if ( _scaled_signal )
+        return _scaled_signal->connected();
+    else
+        return false;
 }
 
 char *