diff --git a/include/osmocom/abis/e1_input.h b/include/osmocom/abis/e1_input.h
index 8cf5c71..9562928 100644
--- a/include/osmocom/abis/e1_input.h
+++ b/include/osmocom/abis/e1_input.h
@@ -100,6 +100,9 @@
 			struct osmo_fd fd;
 			struct lapd_instance *lapd;
 		} dahdi;
+		struct {
+			struct osmo_fd fd;
+		} rs232;
 	} driver;
 };