diff --git a/include/patty/ax25.h b/include/patty/ax25.h
index 41ffe02..84746b1 100644
--- a/include/patty/ax25.h
+++ b/include/patty/ax25.h
@@ -65,6 +65,9 @@ enum patty_ax25_param_classes {
     PATTY_AX25_PARAM_CLASSES_FULL_DUPLEX = (1 << 6)
 };
 
+#define PATTY_AX25_PARAM_DEFAULT_CLASSES \
+    (PATTY_AX25_PARAM_CLASSES_ABM)
+
 enum patty_ax25_param_hdlc {
     PATTY_AX25_PARAM_HDLC_REJ        = (1 <<  1),
     PATTY_AX25_PARAM_HDLC_SREJ       = (1 <<  2),