# 1. Basic usage
You can buy this kind of USB box from Taobao for about 20 to 30 yuan. It can be plugged into a computer, PAD, or mobile phone and used directly (for PAD and mobile phone, you need to buy a small accessory that converts USB to a mobile phone charging port, which costs about a few yuan).
The essence of this kind of box is a keyboard. You can use it as a keyboard, such as back-end product management, and the input box for barcodes. Originally, you entered it with the keyboard. When your cursor is in the input box, scan the code against the QR code box, and it will automatically fill it in for you. In fact, it has no special function.
So to sum up, any input box that is originally entered by keyboard can be automatically filled in for you by scanning the box. The same principle applies to mobile phones.
# 2. If it is unattended, can users self-service verification? Or is the coupon user’s self-service verification unattended?
This function can be implemented using the mobile backend:
**Mini program version:**
Android mobile version:
After logging in to your account, follow the process below to open the self-service verification interface:
After entering this page, there is no need to worry about it. The user can present the write-off code and scan it into the scanning box. There will be a voice broadcast of the write-off result.