# Message Type Indicator Mti

#### ISO Version

| Code | Description     |
| ---- | --------------- |
| 0xxx | ISO 8583:1987   |
| 1xxx | ISO 8583:1993   |
| 2xxx | ISO 8583:2003   |
| 3xxx | Reserved by ISO |
| 4xxx | Reserved by ISO |
| 5xxx | Reserved by ISO |
| 6xxx | Reserved by ISO |
| 7xxx | Reserved by ISO |
| 8xxx | National use    |
| 9xxx | Private use     |

#### **Message class**

| **Code** | Description                      | Usage                                                                                                                                                                                                                                   |
| -------- | -------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| x0xx     | Reserved by ISO                  |                                                                                                                                                                                                                                         |
| x1xx     | Authorization message            | Determine if funds are available, get an approval but do not post to account for reconciliation. Dual message system (DMS), awaits file exchange for posting to the account.                                                            |
| x2xx     | Financial messages               | Determine if funds are available, get an approval and post directly to the account. Single message system (SMS), no file exchange after this.                                                                                           |
| x3xx     | File actions message             | Used for hot-card, TMS and other exchanges                                                                                                                                                                                              |
| x4xx     | Reversal and chargeback messages | <p>Reversal (x4x<strong>0</strong> or x4x<strong>1</strong>): Reverses the action of a previous authorization.<br>Chargeback (x4x<strong>2</strong> or x4x<strong>3</strong>): Charges back a previously cleared financial message.</p> |
| x5xx     | Reconciliation message           | Transmits settlement information message.                                                                                                                                                                                               |
| x6xx     | Administrative message           | Transmits administrative advice. Often used for failure messages (e.g., message reject or failure to apply).                                                                                                                            |
| x7xx     | Fee collection messages          |                                                                                                                                                                                                                                         |
| x8xx     | Network management message       | Used for secure key exchange, logon, echo test and other network functions.                                                                                                                                                             |
| x9xx     | Reserved by ISO                  |                                                                                                                                                                                                                                         |

#### **Message function**

| Code | Meaning                     |                                                                                      |
| ---- | --------------------------- | ------------------------------------------------------------------------------------ |
| xx0x | Request                     | Request from acquirer to issuer to carry out an action; issuer may accept or reject  |
| xx1x | Request response            | Issuer response to a request                                                         |
| xx2x | Advice                      | Advice that an action has taken place; the receiver can only accept, not reject      |
| xx3x | Advice response             | Response to an advice                                                                |
| xx4x | Notification                | Notification that an event has taken place; the receiver can only accept, not reject |
| xx5x | Notification acknowledgment | Response to a notification                                                           |
| xx6x | Instruction                 | ISO 8583:2003                                                                        |
| xx7x | Instruction acknowledgment  | ISO 8583:2003                                                                        |
| xx8x | Reserved for ISO use        | Some implementations (such as MasterCard) use for positive acknowledgment.           |
| xx9x | Reserved for ISO use        | Some implementations (such as MasterCard) use for negative acknowledgment.           |

#### **Message origin**

| Code | Title           |
| ---- | --------------- |
| xxx0 | Acquirer        |
| xxx1 | Acquirer repeat |
| xxx2 | Issuer          |
| xxx3 | Issuer repeat   |
| xxx4 | Other           |
| xxx5 | Other repeats   |
| xxx6 | Reserved by ISO |
| xxx7 | Reserved by ISO |
| xxx8 | Reserved by ISO |
| xxx9 | Reserved by ISO |