diff --git a/include/osmocom/abis/e1_input.h b/include/osmocom/abis/e1_input.h
index acbc110..9825999 100644
--- a/include/osmocom/abis/e1_input.h
+++ b/include/osmocom/abis/e1_input.h
@@ -151,6 +151,7 @@
 	S_INP_NONE,
 	S_INP_TEI_UP,
 	S_INP_TEI_DN,
+	S_INP_TEI_UNKNOWN,
 	S_INP_LINE_INIT,
 	S_INP_LINE_ALARM,
 	S_INP_LINE_NOALARM,