=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= = P/HUN Issue #3, Volume 2: Phile #10 of 11 = =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= PLASTIC CARD ENCODING PRACTICES AND STANDARDS --------------------------------------------- By Hasan Ali For P/HUN Issue #3 GENERAL PHYSICAL CHARACTERISTICS -------------------------------- If you take any plastic card (MasterCard, VISA, AMEX, ATM cards, etc.) and turn it over you will find a thin black strip of magnetic material. This strip has the ability to hold multiple "tracks" or bands of encoded data. There are 3 valid tracks. Track 1 is the track nearest to the top of the card, and it is followed by Tracks 2 and 3. The original specifications allowed for Tracks 1 and 2 only, and they are both read-only. The additional Track 3 furnishes an ability to read OR write. TRACK 1 The International Airlines Transport Association originated the development of Track 1 as the official track airline use and, in fact, it defined the data and encoding formats for the ANSI standard. This track was originally designed to allow the use of customer-operated ticket dispensing machines to cut down the traffic at airport ticket counters. Now, many other parties make use of Track 1 because it is the only encoded track that permits encoding of the card holder's name. With this alphanumeric capacity, the card holder's name can be printed on an EFT terminal receipt rather cheaply, otherwise the name would have to be sent the computer, which would be more costly and would take more time. There are 26 formats for Track 1, and they are designated by codes from "A" to "Z". Format "B" is shown below. Field Name Length(chars) Start sentinel 1 Format code = "B" 1 (alpha only) Primary account number Up to 19 Separator (SEP) 1 Country code 3 Name 2 to 26 Surname Surname SEP = "/" First name or initial Space (when required) Middle name or initial Period (when followed by title) Title (when used) SEP 1 Expiration date or SEP 4 or 1 Discretionary data balance up to maximum track length End sentinel 1 Longitudinal Redundancy Check (LRC) 1 MAXIMUM TRACK LENGTH 79 Format code "A" is reserved for proprietary use by the card issuer. Format codes "C" through "M" are reserved by ANSI for use in other data formats of Track 1. Format codes "N" through "Z" are available for use by individual card issuers. TRACK 2 The American Bankers Association led to the development of Track 2 on behalf of two credit card companies (Interbank and VISA) and their members. The intent was to have a standardized plastic card which could be used at point- of-sale (POS) terminals to obtain authorization for credit card transactions. Today, in the financial industry, Track 2 is the most widely used encoding method for plastic cards. It has a strong following because most EFT terminals are connected directly to a computer that accesses the cardholder's data files. Also, it is the preferred choice of the ABA and is the only track recognized and supported by MasterCard and VISA. The format of Track 2 is shown below. Field Name Length (chars) Start sentinel 1 Primary account number up to 19 SEP 1 Country code 3 Expiration date or SEP 4 or 1 Discretionary data balance up to maximum track length End sentinel 1 LRC 1 MAXIMUM TRACK LENGTH 40 Although Track 2 is widely accepted, there is a serious potential concern about it because of its limited encoding capacity - only 40 characters. The argument supporting the current capacity stresses that all the necessary information to authorize a transaction is at the data center thereby eliminating the need to encode extraneous data. On the other hand, those suggesting that the capacity be increased feel that greater capacity would allow certain transactions to be approved directly at the terminal, or, at least, minimize data sent between terminal and computer for each transaction. Those who hold this view are using Tracks 1 and 3. TRACK 3 Track 3 was developed for use in off-line EFT terminals but was designed to be compatible with other plastic card standards. Thus, Track 3 is compatible with the ANSI standard for embossing plastic cards and the ANSI standard for physical characteristics of magnetic stripes. More recently, financial institutions have started to use it in on-line systems because of its greater data storage capacity. The format of Track 3 follows. Field Name Usage Status Length (chars) Start sentinel M S 1 Format Code M S 2 Primary account number (PAN) M S 19 SEP M S 1 Country code or SEP M S 3 or 1 Currency M S 3 Currency exponent M S 1 Amount authorized per M S 4 cycle period Amount remaining this cycle M D 4 Cycle begin M D 4 Cycle length M S 2 Retry count M D 1 PIN control parameters or SEP M S 6 or 1 Interchange control M S 1 Type of account and M S 2 service restriction (PAN) Type of account and M S 2 service restriction (SAN-1) Type of account and M S 2 service restriction (SAN-2) Expiration date or SEP M S 4 or 1 Card sequence number M S 1 Card security number or SEP M S 9 or 1 First subsidiary account O S variable number (SAN-1) SEP M S 1 Second subsidiary account O S variable number (SAN-2) SEP M S 1 Relay marker M S 1 Crypto check digits or SEP M D 6 or 1 Discretionary data O D variable End sentinel M S 1 LRC M D 1 MAXIMUM TRACK LENGTH 107 "M" - Mandatory field "O" - Optional field "D" - Dynamic field - may be modified by appropriate interchange partners "S" - Static field - may only be modified by card issuer For further information on these topics, find these ANSI publications at your local good technical library: ANSI X4.13-1979 ANSI X4.16-1973 ANSI X4.16-(Draft October 1980) ANSI X9.1-1980