B4J Question Serial receving wrong replies

Sub Process_Globals       
    Private sp As Serial
    
    Private astream As AsyncStreams
    Private connected As Boolean
    
End Sub

Sub AppStart (Args() As String)
        
    sp.Initialize("")
    
    Log(sp.ListPorts)
    connected = False
    
    Connect(sp.ListPorts.Get(1))
    
    StartMessageLoop
End Sub
Sub AStream_NewData (Buffer() As Byte)
    Dim s As String
    s = BytesToString(Buffer, 0, Buffer.Length, "UTF8")
    
    Dim msg() As String
    msg = Regex.Split(CRLF,s)
    
    For x = 0 To msg.Length - 1
        Log("Rx: " & msg(x))   
    Next
End Sub

Sub AStream_Error
    Log("Error: " & LastException)
    astream.Close
    AStream_Terminated
    connected = False
End Sub

Sub AStream_Terminated
    Log("Connection is broken.")
    connected = False
End Sub

Sub Connect(ComPort As String)
    Log("Connecting to Port: " & ComPort)
    
    sp.Open(ComPort)
    sp.SetParams(9600,8,1,0)
    astream.Initialize(sp.GetInputStream, sp.GetOutputStream, "astream")
    
    connected = True

    SendData("ABC123")

End Sub

Public Sub SendData(msg As String)
    Log("connected = " & connected)
    Log("Send: " & msg)
    If connected Then astream.Write(msg.GetBytes("UTF8"))
End Sub

Connecting to Port: COM3
connected = true
Send: ABC123
Rx: 870003
Rx: 612401011901291
Rx: 721264e
Rx: 8700036122000
Rx: 119012917212651

Tx: ABC123
Rx: 8700036124010119012917230270
Rx: 8700036122000119012917230273