Almost all ordinary printed matter is sorted by hand, because the standardization of such mails handed in by the society is very low, and it is impossible to sort them on the computer;
In a large processing center, some business letters (reports, etc. Due to the high degree of standardization, it can be sorted by sorting machine, but due to the correctness of postal code and address mastered by enterprises and the limited processing accuracy of sorting machine, a considerable number of letters are still sorted by hand; However, parcel mails are basically sorted by machines in relatively large processing centers, and the correct rate is relatively high.
According to the postal law, letters should be sorted by postal code, and the address is only used to indicate the specific name and address at the time of delivery, but the correct rate of filling in postal code by customers is relatively low, so now they are basically sorted by address, and the labor/machine cost of sorting by address is high and it is easy to make mistakes. The post office is now preparing to increase the optimization and publicity of postal codes.
That's basically it. .