Payment Cards - Magnetic Track Data

ISO/IEC 7813 defines following properties of financial transaction cards:
  • physical characteristics, such as size, shape, location of magnetic stripe, etc.
  • magnetic track data structures for encoding three tracks on a magnetic stripe card.

A track is a line on the magnetic stripe over which encoded data are recoded. There are 3 tracks on magnetic stripe, which are referred serially as Track-1, Track-2 and Track-3. The standards define the recording density of each track and it varies for each track. The recording density is referred to as BPI, or bits-per-inch.

Track-1

Track-1 contains alphanumeric characters, recorded at 210 BPI at 7 bits per character.

In case of a credit card, this track normally encodes the cardholder’s name, card number and card expiry date. Field separator and placeholder characters are also found on the track.

Debit cards also contain the same information but to avoid delay in issuing a card when a customer opens an account, Banks now-a-days keep readymade cards. While generating these cards, all info like card number, expiry date, service code, PVV, CVV are available with the Bank but not the name; not even the details of any Bank account. PIN is also printed and kept separately. These cards therefore contain all information other than the name of the customer. The name is linked with the card in the Card Application at the time of account opening but will not be encoded on it.

Banks that still follow the procedure of generating cards after the account is opened – like with credit cards – and mailing it to customer, manage to get the customer name on the card.

To know the difference, while using these cards, if the ATMs just stop with saying “Hello” without any name, then it is a readymade card else it was generated exclusively for you.

Name does not affect the functionality of the payment system. Core Banking System contains all account details including name and address, where CUSTOMER gets centre-stage while in card processing the CARD takes centre-stage. More on this when we discuss Transaction Switch software.

Track-2

Track-2 contains only numeric data, recorded at 75 BPI at 5 bits per character. It’s limit is 40 characters. This track contains cardholder’s card number and expiry date. While these two pieces of data are also found on Track-1, the reasons for placing them on Track-2 are twofold. Firstly, it provides an extra degree of redundancy on the card, should one of the tracks be erased or become unreadable.

Track-3

Track-3 is used rarely, if at all, and its content is numeric only, recoded at 210 BPI, 5 bits per character. It is termed the “Thrift Track.” It was designed by the Thrift Industry to support read-write function that enables this track to be updated with each transaction. It is not difficult to guess as to why Banking system doesn’t patronise it. Look below at the kind of data a Bank needs to encode if it were to use Track-3. The “Currency code” is one among them. One could change it to USD after bank encodes it as INR leading to withdrawal of USDs in place INRs. “Amount authorized per cycle” from 20000 to 50000 thus increasing everyday withdrawal limit; or the “Amount remaining in this cycle” could be enhanced from say 5000 to 30000. Now the risks are known. It is quite unsafe for Banks and so they don’t use it all. They use the minimal data available in Track-2. Remaining controls are all managed by the Transaction switch.

Independent use of track 3 is an alternative mode of operation permitting both on-line and off-line data interchange, based on mutual agreement between interested parties. It requires reading only of the data on track 3 and, if update is required, the rewriting of all the data on track 3.

Up to 107 characters can be placed on Track-3 as defined by ISO/IEC 4909 standards.

Single, Dual, and Triple track Card Readers and Encoders are available. Dual track equipments could read tracks 1 & 2 or 2 & 3.

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