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Cards with a microprocessor have a service code value (see clause 1.3) equal to 2xx for international cards and bxx for cards circulating only within the country. The service code is present both on the magnetic stripe of the card and in the mandatory Track 2 Equivalent Data (Tag '57') of the microprocessor card. The data in the Track 2 Equivalent Data object and on the magnetic stripe must be identical except for the CVC / CW values, which will be discussed in section 6.6. The terminal and the servicing bank use this data to generate an authorization request to the issuer.
If the service code of the 1xx or 5xx type is printed on the magnetic stripe of the card, then in this case the terminal considers such a card as a card containing only a magnetic stripe. Therefore, a transaction with such a card is made on the basis of data read from the magnetic stripe of the card (we are talking about accepting a card in an electronic terminal).
An electronic POS terminal, depending on its ability (availability of an appropriate card reader and application software), can be one of the following types:
If the card is used in the terminal of the first type, then regardless of the value of the service code of the card, it will be processed as a card with a magnetic stripe. If a terminal of the second type (hybrid terminal) is used, then the basic rule is that when a card with a 2xx or bxx service code is received, the terminal must first try to carry out an operation using the chip and, only if for some technical reason, it cannot be done, try perform a magnetic stripe operation. In other words, microprocessor technology takes precedence over magnetic stripe technology when both the terminal and the card support this technology.
When the terminal has two separate readers for reading card data (magnetic stripe reader and microprocessor reader), it may happen that the cashier at the point of sale tries to perform the operation on the magnetic stripe first. In this case, the terminal application, by the value of the service code read from the second track of the magnetic stripe, must determine the need to perform an attempt to process the card using the chip and inform the cashier of the merchant about this.
The general scheme of card processing in a hybrid terminal (the cases of CAT terminals are not considered) is shown in Fig. 4.2. The diagram describes both types of hybrid terminals: a terminal with two separate readers (for magnetic stripe and chip) and a terminal with a combined reader capable of simultaneously reading data from the magnetic stripe and chip. In the case of a combined reader, transaction processing begins with the Chip Reader block.
In some cases, a transaction cannot be processed using a chip. The reasons for this can be very varied, starting with the fact that the terminal has established that it cannot select one of the applications it supports on the card chip, and ending with various types of incompatibility between the card and the terminal. All these types of incompatibilities are a consequence of the card and / or terminal not meeting the EMV standard and / or payment system application specifications. (Typical cases of non-compliance with the requirements of the EMV standard will be discussed in section 6.5.)
If the transaction cannot be processed using the chip, the terminal may decide to switch to the magnetic stripe card service. If the reason for the transition to the magnetic stripe was an incompatibility between the card and the terminal, then otherwise in the card jargon it is usually called a fallback (from English, fallback) to the magnetic stripe.
For transactions served in fallback mode, the following rule, adopted by leading payment systems, applies: all transactions in fallback mode must be performed in real time and have:
If the service code of the 1xx or 5xx type is printed on the magnetic stripe of the card, then in this case the terminal considers such a card as a card containing only a magnetic stripe. Therefore, a transaction with such a card is made on the basis of data read from the magnetic stripe of the card (we are talking about accepting a card in an electronic terminal).
An electronic POS terminal, depending on its ability (availability of an appropriate card reader and application software), can be one of the following types:
- a terminal capable of processing transactions only with cards with a magnetic stripe and not capable of processing transactions with microprocessor cards;
- a terminal capable of processing transactions using both magnetic stripe cards and microprocessor cards (hybrid terminal).
If the card is used in the terminal of the first type, then regardless of the value of the service code of the card, it will be processed as a card with a magnetic stripe. If a terminal of the second type (hybrid terminal) is used, then the basic rule is that when a card with a 2xx or bxx service code is received, the terminal must first try to carry out an operation using the chip and, only if for some technical reason, it cannot be done, try perform a magnetic stripe operation. In other words, microprocessor technology takes precedence over magnetic stripe technology when both the terminal and the card support this technology.
When the terminal has two separate readers for reading card data (magnetic stripe reader and microprocessor reader), it may happen that the cashier at the point of sale tries to perform the operation on the magnetic stripe first. In this case, the terminal application, by the value of the service code read from the second track of the magnetic stripe, must determine the need to perform an attempt to process the card using the chip and inform the cashier of the merchant about this.
The general scheme of card processing in a hybrid terminal (the cases of CAT terminals are not considered) is shown in Fig. 4.2. The diagram describes both types of hybrid terminals: a terminal with two separate readers (for magnetic stripe and chip) and a terminal with a combined reader capable of simultaneously reading data from the magnetic stripe and chip. In the case of a combined reader, transaction processing begins with the Chip Reader block.
In some cases, a transaction cannot be processed using a chip. The reasons for this can be very varied, starting with the fact that the terminal has established that it cannot select one of the applications it supports on the card chip, and ending with various types of incompatibility between the card and the terminal. All these types of incompatibilities are a consequence of the card and / or terminal not meeting the EMV standard and / or payment system application specifications. (Typical cases of non-compliance with the requirements of the EMV standard will be discussed in section 6.5.)
If the transaction cannot be processed using the chip, the terminal may decide to switch to the magnetic stripe card service. If the reason for the transition to the magnetic stripe was an incompatibility between the card and the terminal, then otherwise in the card jargon it is usually called a fallback (from English, fallback) to the magnetic stripe.
For transactions served in fallback mode, the following rule, adopted by leading payment systems, applies: all transactions in fallback mode must be performed in real time and have:
- POS Entry Data (DE 022) = 80x in the MasterCard system;
- DE60.3 = “1” (Fallback. No info about chip read error on previous transaction in that terminal) or “2” (Fallback. There was chip read error on previous transaction in that terminal) in VISA.
- - if it follows from the response to the SELECT command that the card is blocked;
- - if it follows from the response to the SELECT command that the selected card application is blocked;
- - after the completion of the transaction on the chip (the card returned the TC or AAS cryptogram to the terminal);
- - if a manual error has occurred (the card is removed from the terminal before the operation is completed, the card is incorrectly inserted into the reader) or a terminal error (loss of power supply, etc.).
