diff --git a/include/osmocom/core/signal.h b/include/osmocom/core/signal.h
index cd56f68..b3a5aae 100644
--- a/include/osmocom/core/signal.h
+++ b/include/osmocom/core/signal.h
@@ -18,6 +18,7 @@
 enum {
 	SS_L_GLOBAL		= OSMO_SIGNAL_SS_RESERVED,
 	SS_L_INPUT,
+	SS_L_NS,
 };
 
 /* application-defined signal types. */