How it works？
1. When car comes, the operator enters the parking time and license plate number on the POS terminal
2. POS Terminal prints a ticket including date, time, license plate number and operator id, also can be generated a bar code or qr code with these info.
3. When the car leaving, car owner gives the ticket to operator, then operator check the time and POS will calculate how much it costs. Operator can also scan the bar code or QR code of ticket, which will auto calculate how much will cost.
4. If it exceeds the time, the POS will print the receipt with extra payment.
