System properties of line cards:

2.3.2 Card number structure

American Express-The 3rd and 4th digits indicate the card type.

And bits 5 to 1 1 indicate the card account number, and bits 12 to 14 indicate the card account number.

The number is the serial number of the card in the account, and the number 15 is the check bit.

Visa- the second to sixth digits are the bank code, and the seventh digit is 12 or the first digit.

7 to 15 is the account number of the card, and 13 or 16 is the last digit.

One bit) is a parity bit.

MasterCard-second and third, second to fourth, second to fifth.

Bit or bit 2 to bit 6 is the bank code (depending on bit 2

When the word is 1, 2, 3 or something). The bank code is followed by it.

The number 15 is the card account number, and the number 16 is the check bit.