diff --git a/include/openbsc/abis_rsl.h b/include/openbsc/abis_rsl.h
index cbbb797..219fdd3 100644
--- a/include/openbsc/abis_rsl.h
+++ b/include/openbsc/abis_rsl.h
@@ -244,6 +244,45 @@
 #endif
 } __attribute__ ((packed));
 
+/* Chapter 9.3.26 */
+#define RSL_ERRCLS_NORMAL		0x00
+#define RSL_ERRCLS_RESOURCE_UNAVAIL	0x20
+#define RSL_ERRCLS_SERVICE_UNAVAIL	0x30
+#define RSL_ERRCLS_SERVICE_UNIMPL	0x40
+#define RSL_ERRCLS_INVAL_MSG		0x50
+#define RSL_ERRCLS_PROTO_ERROR		0x60
+#define RSL_ERRCLS_INTERWORKING		0x70
+
+#define RSL_ERR_RADIO_IF_FAIL		0x00
+#define RSL_ERR_RADIO_LINK_FAIL		0x01
+#define RSL_ERR_HANDOVER_ACC_FAIL	0x02
+#define RSL_ERR_TALKER_ACC_FAIL		0x03
+#define RSL_ERR_OM_INTERVENTION		0x07
+#define RSL_ERR_EQUIPMENT_FAIL		0x20
+#define RSL_ERR_RR_UNAVAIL		0x21
+#define RSL_ERR_TERR_CH_FAIL		0x22
+#define RSL_ERR_CCCH_OVERLOAD		0x23
+#define RSL_ERR_ACCH_OVERLOAD		0x24
+#define RSL_ERR_PROCESSOR_OVERLOAD	0x25
+#define RSL_ERR_RES_UNAVAIL		0x2f
+#define RSL_ERR_TRANSC_UNAVAIL		0x30
+#define RSL_ERR_SERV_OPT_UNAVAIL	0x3f
+#define RSL_ERR_ENCR_UNIMPL		0x40
+#define RSL_ERR_SEV_OPT_UNIMPL		0x4f
+#define RSL_ERR_RCH_ALR_ACTV_ALLOC	0x50
+#define RSL_ERR_INVALID_MESSAGE		0x5f
+#define RSL_ERR_MSG_DISCR		0x60
+#define RSL_ERR_MSG_TYPE		0x61
+#define RSL_ERR_MSG_SEQA		0x62
+#define RSL_ERR_IE_ERROR		0x63
+#define RSL_ERR_MAND_IE_ERROR		0x64
+#define RSL_ERR_OPT_IE_ERROR		0x65
+#define RSL_ERR_IE_NONEXIST		0x66
+#define RSL_ERR_IE_LENGTH		0x67
+#define RSL_ERR_IE_CONTENT		0x68
+#define RSL_ERR_PROTO			0x6f
+#define RSL_ERR_INTERWORKING		0x7f
+
 /* Chapter 9.3.30 */
 #define RSL_SYSTEM_INFO_8	0x00
 #define RSL_SYSTEM_INFO_1	0x01