Photo of a POS terminal related to EMV Issuer Action Code settings

These are codes that communicate the issuer's conditions for approving a transaction online (IAC-Online), for declining a transaction (IAC-Denial), or, if the terminal is unable to go online, for declining the transaction (IAC-Default).

Each IAC/TAC list has 3 separate types: Online, Denial and Default.

IAC – Online

Defines the issuer's conditions for approving the transaction online. For example;

Issuer Action Code - Online: FC68BC9800
  Byte 1: 
    Offline data authentication was not performed (b8)
    SDA failed (b7)
    ICC data missing (b6)
    Card appears on terminal exception file (b5)
    DDA failed (b4)
    CDA failed (b3)
  Byte 2: 
    Expired application (b7)
    Application not yet effective (b6)
    New card (b4)
  Byte 3: 
    Cardholder verification was not successful (b8)
    PIN Try Limit exceeded (b6)
    PIN entry required and PIN pad not present or not working (b5)
    PIN entry required, PIN pad present, but PIN was not entered (b4)
    Online PIN entered (b3)
  Byte 4: 
    Transaction exceeds floor limit (b8)
    Transaction selected randomly for online processing (b5)
    Merchant forced transaction online (b4)
  Byte 5:

TVR byte 2 b4 value is 1 (New Card). This value corresponds to Issuer Action Code – Online.
As a result, the terminal will send the transaction online to the issuer bank.

IAC – Denial

States the issuer's conditions for declining the transaction.

For example;

Issuer Action Code - Denial: 0010180000
  Byte 1: 
  Byte 2: 
    Requested service not allowed for card product (b5)
  Byte 3: 
    PIN entry required and PIN pad not present or not working (b5)
    PIN entry required, PIN pad present, but PIN was not entered (b4)
  Byte 4: 
  Byte 5:

If the value of byte 3 b5 is set to 1 in both the TVR and the IAC, this means the transaction will be declined.

IAC – Default

If the terminal has no online connection, the IAC – Default list states the issuer conditions under which the transaction will be declined.

For example;

Issuer Action Code - Default: FC40AC8000
  Byte 1: 
    Offline data authentication was not performed (b8)
    SDA failed (b7)
    ICC data missing (b6)
    Card appears on terminal exception file (b5)
    DDA failed (b4)
    CDA failed (b3)
  Byte 2: 
    Expired application (b7)
  Byte 3: 
    Cardholder verification was not successful (b8)
    PIN Try Limit exceeded (b6)
    PIN entry required, PIN pad present, but PIN was not entered (b4)
    Online PIN entered (b3)
  Byte 4: 
    Transaction exceeds floor limit (b8)
  Byte 5:

If the value of TVR and IAC byte 4 b8 is 1, the transaction will be declined.