diff --git a/include/openbsc/e1_input.h b/include/openbsc/e1_input.h
index bf91b49..e127c27 100644
--- a/include/openbsc/e1_input.h
+++ b/include/openbsc/e1_input.h
@@ -16,6 +16,7 @@
 	E1INP_SIGN_OML,
 	E1INP_SIGN_RSL,
 };
+const char *e1inp_signtype_name(enum e1inp_sign_type tp);
 
 struct e1inp_ts;
 
@@ -50,6 +51,7 @@
 	E1INP_TS_TYPE_SIGN,
 	E1INP_TS_TYPE_TRAU,
 };
+const char *e1inp_tstype_name(enum e1inp_ts_type tp);
 
 /* A timeslot in the E1 interface */
 struct e1inp_ts {