diff --git a/libs/ardour/ardour/jack_port.h b/libs/ardour/ardour/jack_port.h
index 3fa0008e17..e19af25fd1 100644
--- a/libs/ardour/ardour/jack_port.h
+++ b/libs/ardour/ardour/jack_port.h
@@ -51,6 +51,9 @@ class JackPort : public virtual Port, public PortConnectableByName {
 	int reconnect ();
 
 	int connect (Port& other) {
+		if( _flags & IsOutput ) {
+		    return 0;
+		}
 		return connect (other.name());
 	}