Android Question How use USB Host for special board?

[darabon]

I have a device named STM32 Virtual COM Port
According to link https://www.b4x.com/android/forum/threads/android-usb-host-tutorial-adbtest.11289/#content
I try to connect to the device and send data to it
After press Connect, allow permission and try to connect to the device
I try InterfaceClass number and also subclass and handle device for send data
But I don't know what is InterfaceClass and InterfaceSubclass
In the RealTerm software, my setting is below picture and there is no problem but cannot connect to it in android:

 

[Erel]

You need to check whether USBSerial2 of felUsbSerial support this adapter.

 

[darabon]

You need to check whether USBSerial2 of felUsbSerial support this adapter.

No that isn't an adapter, actually, that is a microcontroller
I found a probem
I changed InterfaceClass to 10 and now I can read and write data to micro
Thanks

 

[darabon]

Sorry, I have a problem in reading data
My data length is 180 but SendOutRequest("Msg", msg, 24) set to 24
I tried change that but result is invalid (data are not complete)
Please help me