Dual screen display API is a Android common API.You can check the Android developer guide.
https://developer.android.google.cn/reference/android/app/Presentation
This is Android official SDK,you can also check this.
Also we have a demo and source code for you reference.https://mega.nz/file/argHTQxK#vSDNQUGA9RKe_HnrUo8DWRDDMOU-gxAgNb3HJHksdyQIt is also fit for other cash register like C1,C2,C8 etc.