| 1 | OK response | 
|  | No further information. | 
| 2 | Syntax error | 
|  | Error detected in syntax. | 
| 3 | Invalid header | 
|  | Invalid header segment received. | 
| 4 | Invalid trailer segment | 
|  | Invalid trailer segment received. | 
| 5 | Unsupported syntax | 
|  | Syntax version/release not supported. | 
| 6 | Unsupported scenario type | 
|  | Scenario type not supported. | 
| 7 | Unsupported scenario version | 
|  | Scenario version/release not supported. | 
| 8 | Unsupported dialogue type | 
|  | Dialogue type not supported for this scenario. | 
| 9 | Unsupported dialogue version | 
|  | Dialogue type version/release not supported. | 
| 10 | Unauthorised sender | 
|  | Sender not authorised. | 
| 11 | Sender rejected | 
|  | Sender rejected for administrative reasons. | 
| 12 | Multiple transactions unsupported | 
|  | Multiple parallel transactions not supported. | 
| 13 | Multiple dialogues unsupported | 
|  | Multiple parallel dialogues not supported. | 
| 14 | Resources unavailable | 
|  | Resources unavailable for requested function. | 
| 15 | Unknown transaction | 
|  | Referenced transaction does not exist. | 
| 16 | Unknown dialogue | 
|  | Referenced dialogue does not exist. | 
| 17 | Invalid function | 
|  | Function invalid for current dialogue state. | 
| 18 | Service unavailable | 
|  | Requested service is unavailable. | 
| 19 | Application unavailable | 
|  | Requested application not available. | 
| 20 | Time-out | 
|  | Response not received within expected time. | 
| 21 | Unable to process interactively | 
|  | To notify the initiator that a specific request cannot be processed interactively. | 
| 22 | Correctable application error | 
|  | To notify the initiator that an application error, that is correctable by the initiator, was made in the request message. | 
| 23 | Nothing to return | 
|  | To notify the initiator that there is no information to return in response to an inquiry. | 
| 24 | Data not accessible | 
|  | To notify the initiator that the requested information cannot be returned. | 
| 25 | Non-correctable application error | 
|  | To notify the initiator that some type of system or processing error was encountered, not related to the data received. |