Android Question USB RS232 recive data

Hello, I need to receive RS232 data.
When you receive them and how to receive it I have to decide.
I do this in VB6 with this routine.

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Private Sub tmrAvvio_Timer()
Dim ValRX as String
RxData:
Do
DoEvents
Loop Until MSComm1.InBufferCount >= 1
ValRX = MSComm1.Input
If ValRX = Chr$(173) Then GoTo RxATTESA
GoTo Pollig
end sub

Private Sub RxATTESA()
... ...
end sub

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How can I do it in Basic4Android?

Thank you.
Marco