| iua.asp_identifier | ASP identifier | Unsigned 32-bit integer | |
| iua.asp_reason | Reason | Unsigned 32-bit integer | |
| iua.diagnostic_information | Diagnostic information | Byte array | |
| iua.dlci_one_bit | One bit | Boolean | |
| iua.dlci_sapi | SAPI | Unsigned 8-bit integer | |
| iua.dlci_spare | Spare | Unsigned 16-bit integer | |
| iua.dlci_spare_bit | Spare bit | Boolean | |
| iua.dlci_tei | TEI | Unsigned 8-bit integer | |
| iua.dlci_zero_bit | Zero bit | Boolean | |
| iua.error_code | Error code | Unsigned 32-bit integer | |
| iua.heartbeat_data | Heartbeat data | Byte array | |
| iua.info_string | Info string | String | |
| iua.int_interface_identifier | Integer interface identifier | Signed 32-bit integer | |
| iua.interface_range_end | End | Unsigned 32-bit integer | |
| iua.interface_range_start | Start | Unsigned 32-bit integer | |
| iua.message_class | Message class | Unsigned 8-bit integer | |
| iua.message_length | Message length | Unsigned 32-bit integer | |
| iua.message_type | Message Type | Unsigned 8-bit integer | |
| iua.parameter_length | Parameter length | Unsigned 16-bit integer | |
| iua.parameter_padding | Parameter padding | Byte array | |
| iua.parameter_tag | Parameter Tag | Unsigned 16-bit integer | |
| iua.parameter_value | Parameter value | Byte array | |
| iua.release_reason | Reason | Unsigned 32-bit integer | |
| iua.reserved | Reserved | Unsigned 8-bit integer | |
| iua.status_identification | Status identification | Unsigned 16-bit integer | |
| iua.status_type | Status type | Unsigned 16-bit integer | |
| iua.tei_status | TEI status | Unsigned 32-bit integer | |
| iua.text_interface_identifier | Text interface identifier | String | |
| iua.traffic_mode_type | Traffic mode type | Unsigned 32-bit integer | |
| iua.version | Version | Unsigned 8-bit integer | |