Optional fields may always be present in requests, even when not needed. In such case, they will be ignored. Requests received missing a mandatory field will be 904 - Format Error.

The third party host must ignore unknown fields included in the response messages.

When no usage notes are given in the field description, the field should be used as described in IFSF [1].

The “Format”-column can contain following info:

• LL: Variable length field, max 99 bytes as data. The field contains 2 bytes holding the length of the data. Example: 303101 a one byte field with LL = 3031 and the data is 01.
• LLL: Variable length field, max 999 bytes as data. The field contains 3 bytes holding the length of the data. Example: 30303101 a one byte field with LLL = 303031 and the data is 01.
• Date/time field formats, YYMMDDhhmmss (or variations), where:
  • YY : Last 2 digits of the year, 00 through 99
  • MM: Month, 01 through 12.
  • DD: Day, 01 through 31
  • hh: Hour, 00 through 23
  • mm: Minutes, 00 through 59
  • ss: Seconds, 00 through 59

The “Type”-column can contain:

• a : Alphabetic character [a..z,A..Z]
• n : Numeric BCD-digit. [0..9]
• ans: alphabetic, numeric and special characters
• an : alphabetic and numeric.
• s : Special characters.
• b : Binary
• p: pad character, space
• x: “C” for credit, “D” for debit and shall always be associated with a numerical amount data element.

The “Size”-column can contain:

• Variable length fields have a size that looks like “..nn”, where nn is the maximum number of characters or bytes.
• A fixed length field has “n” as size content, with n the number of characters or bytes.

All fixed length “n” data elements are assumed to be right justified with leading zeroes. All other fixed length data elements are left justified with trailing spaces. In all “b” data elements, blocks of 8 bits are assumed to be left justified with trailing zeroes.

Message protocol

All messages are transferred using TCP/IP sockets.

The message will be encapsulated in a transmission frame as follows:

• The first 4 digits contain the length of the message in ASCII (decimal value, most significant digit first). The length field includes all bytes from the first byte of the message ID up to the last byte of the last field.
• This 4-digit length field is immediately followed by the message ID, also in ASCII (decimal value, most significant digit first).
• An 8 byte message bitmap, which is a binary field (so not ASCII encoded).
• Message fields, which could be ASCII or binary encoded. The fields with format ‘n, ns, an, ans, anp or x’ are ASCII encoded, while the fields with format ‘b’ are binary encoded. The following conventions shall be applied to all data elements:
  • All fixed length numeric data element values shall be right justified with leading zeroes.
  • All fixed length data elements with alphabetic or special characters shall be left justified with trailing blanks.
  • All fixed length binary data elements shall be right justified with leading zeroes.
  • The position of a character or a bit in a data element shall be counted from the left beginning with one (1).(See also section 5.1 Attribute specification in [01])
  • No trailer is included.

Example: An imaginary message which consists only of a message ID “0300” and an empty bitmap (all zeros) will be transmitted as follows:
 

Example: An 1820 message, without MAC, will be transmitted as follows: Message bytes (hex):
303035303138323002300101000000003039313031353238343133383239313030393039313031353238343138333130353130303331

The PayEx response timeout is set to XX seconds. If after xx+1 seconds, no response has been received, the third party host needs to take the appropriate action based on the message type. (E.g. send a reversal)

The third party host has the possibility to perform offline stand-in, thought this needs to be agreed with the indididual card issuers. Otherwise the station might not be reimbursed.

PIN Validation

PayEx perform online PIN validation on paye,ent cards where PayEx is the acquirer, on all other cartds PIN is validated by the third party acuirer.  PayEx will not interpret P-22 Point-Of-Service code to determine if it needs to validate PIN or not on PayEx fuel cards, but 3rd patry aquirers might so it's good practice to use P-22 correctly. 

Fields required for PIN validation are: 

• P-48-14 – PIN encryption Methodology
• P-52 – PIN data
• P-53 – Security related information

Message field details

P-2 PAN

Personal Account Number, identifies the card.Only mandatory for Manual PAN transactions (replacement for Track2Data P35)

P-3 PROCESSING CODE

Code used to describe the effect of a transaction on the customer account and the accounts affected. Fixed 00000000 : Goods and services

P-4 AMOUNT, TRANSACTION

The amount is a numeric value, expressed without a decimal separator. Where a minor unit of currency applies, the relevant minor unit data element indicates the number of decimal places in the relevant amount.  Example : 1 kr = 100

P-7 DATE AND TIME, TRANSMISSION

Date and time of message transmission from the third party host. 

P-11 SYSTEM TRACE AUDIT NUMBER

Number assigned by the third party host to assist in identifying a transaction uniquely. Range 000001 till 999999. Every message must have a new STAN, repeats use the same STAN as the original message.
P-12 DATE AND TIME, LOCAL TRANSACTION

Date and time of the transaction when performed on the POS. 

P-14 DATE EXPIRY

Month and year of card expiry. Only mandatory for a manual PAN transaction

P-22 POINT OF SERVICE DATA CODE

A series of codes intended to identify terminal capability, terminal environment and presentation security data.

P-24 FUNCTION CODE

P-25 MESSAGE REASON CODE

P-30 ORIGINAL AMOUNT

The original amount data element is a constructed element of two parts with a total of 24 positions:
a)    Original amount transaction, n 12;
b)    Original amount reconciliation, n 12.
Absence of data shall be indicated by zeroes. These parts shall be used when attempting to perform a partial approval and shall contain the original amounts.

P-32 ACQUIRING INSTITUTION IDENTIFICATION CODE

ISO 3166 - numeric country code of country where the POS transaction took place.

P-33 FORWARDING INSTITUTION IDENTIFICATION CODE

10 digit code identifying the 3rd patry host. Each 3rd party integrated with PayEx will be assigned a unique code that they are to use in all messages where P-33 is specified. 

P-35 TRACK 2 DATA

The information encoded on track 2 of the magnetic stripe as defined in ISO7813, excluding beginning and ending sentinels and longitudinal redundancy check characters as defined therein.

Example: 123456789012345=00112233

P-38 APPROVAL CODE

Code assigned by the authorising institution indicating approval.

P-39 ACTION CODE

The following action codes are supported by OASE. Every action code not present in this table should be considered as declined.