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POS Architecture ​

What is a POS System? ​

A Point of Sale (POS) system is a combination of hardware and software that allows businesses to process transactions with customers. It typically includes a cash register, barcode scanner, receipt printer, and payment terminal. Modern POS systems are often integrated with inventory management, customer relationship management (CRM), and analytics tools to provide businesses with a comprehensive solution for managing sales operations.

Architecture ​

POS Device ​

The POS device is the central component of the system. It initiates the payment process when a user enters an amount to be paid.

Payment Channels ​

The POS device then directs the user to the payment channels, which are the different methods of payment available.

Search Card ​

Once the user selects a bank card as their payment method, the system searches for the card.

Read Card ​

The card is then read by the card reader. The card reader detects the mode in which the card is being used (inserted, tapped, or swiped).

Card Mode Detection ​

Depending on the card mode, the system processes the card accordingly:

  • INSERT: The card is processed as an Integrated Circuit (IC) card.
  • TAP: The card is processed as a Radio Frequency (RF) card.
  • SWIPE: The card is processed as a Magnetic Access (MAG) card.

Process IC, Process RF, Process MAG ​

These steps represent the processing of the card in each respective mode.

AES Encryption ​

After the card is processed, the track data is encrypted using AES encryption.

Charge on Server ​

The encrypted data is then sent to the server for charging.

Success Screen, Error/Failure Screen ​

Depending on the server's response, the user is presented with either a success screen or an error/failure screen.

If the transaction is successful, a receipt is printed. If there is an error, the user can choose to print a receipt or try again.

EMV Process ​

The EMV process is initiated for IC cards, which involves starting an EMV listener and extracting track data.

Listener Callbacks ​

The EMV listener handles callbacks for track data extraction.

Track Data from INSERT, Track Data from TAP ​

These steps represent the extraction of track data from the card in the respective modes.

Pin Pad ​

The user enters their PIN at the pin pad.

EMV Result ​

The system processes the EMV result, which can be successful, canceled by the user, or a failure.

AES Encryption (2) ​

If the EMV result is successful, the track data is encrypted again before being sent to the charging API.

Charging API ​

The encrypted data is sent to the charging API, which attempts to charge the card.

Charge on Server (2) ​

The charging API communicates with the server to charge the card.

This architecture ensures that the payment process is secure and that the user is informed of the transaction's outcome. It also allows for the possibility of retrying the transaction in case of failure.