Financial Business (2)-architecture of the Self-settlement business system of banks ()

This thesis is intended for technical developers who are interested in banking. I try to describe the architecture of the Self-settlement business system in a language that ordinary readers can understand.
Before talking about it, we should first elaborate on the concept of UnionPay:
UnionPay is the consortium of various banks. All banks that join unionpay are the shareholders of UnionPay. UnionPay's main business is self-settlement and settlement services such as POS and ATM. UnionPay pays online, internet mobile payment services.
Before UnionPay is available, the architecture of the self-service settlement business system is as follows:
That is, the settlement terminal forwards the transactions based on different bank cards to the corresponding bank. In fact, the self-settlement terminals deployed by banks only accept the business of the bank. Therefore, the functions of the Self-settlement terminal are extremely limited. For example, the self-settlement terminal deployed in the postal savings can only accept the business of the postal savings card.
UnionPay came into being to accept cards from all banks. Then the system architecture is like the following:
This architecture can accept all bank card transactions, and the transactions are forwarded to various banks through UnionPay. Therefore, UnionPay has formulated a unified self-settlement business standard, and end suppliers develop according to UnionPay's unified standards. This architecture is the terminal deployed by UnionPay.
A unified standard can accept a unified business, but it is inconvenient for a bank to develop its own special business on the self-service settlement terminal. As a result, a better architecture emerged and is also the most popular system architecture of the banking self-service settlement business. For more information, see:
 
For the terminal deployed by XX Bank, if it is the business of XX Bank, it will be accepted directly in its own bank, and the business of other banks will be sent to UnionPay, the Bank's own special business can be sent to the corresponding business system through its own business system. This satisfies the needs of the market .? [The business introduction for each phase will be sent to the yuyun region subscription number. Welcome to note (bbs.360inhands.com )]