This is a demo found on the Internet. The device connection and communication are normal. I have also tried to write data, but the read data cannot be obtained. After $SerialNumber is passed in, there is no change.
This is the definition of SDK
After running
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
This is really hard to reply to. Is there a technical service for the attendance machine? Is there a manual?