B4J Question astream.write - comm error

Text = "QMOD" & Chr(73) & Chr(193) & Chr(13)  '(command + CRC + cr)
MSComm2.Output = Text
Sleep (200)
Rx = MSComm2.Input

#Region  Project Attributes
    #CommandLineArgs:
    #MergeLibraries: True
#End Region

Sub Process_Globals
    Private myserial As Serial
    Private astream As AsyncStreams
    Private uart_list As List
    Private sndStr As String
    Private rcvStr As String
    Private text As String = "QMOD" & Chr(73) & Chr(193) & Chr(13)
   
   
End Sub

Sub AppStart (Args() As String)
    myserial.Initialize("")
    uart_list = myserial.ListPorts
    myserial.Open("COM7")
    myserial.SetParams(2400,8,1,0)
    astream.Initialize(myserial.GetInputStream,myserial.GetOutputStream,"astream")
    Log("Initialized")
    Log("Text --> " & text)
    astream.Write(text.GetBytes("UTF8"))
    Wait(0.2)
   
    StartMessageLoop
   
End Sub

Sub astream_NewData (Buffer() As Byte)
    rcvStr = BytesToString(Buffer, 0, Buffer.Length, "UTF8")
    sndStr = "I have received " & rcvStr & Chr(13) & Chr(10)
    Log(sndStr)
End Sub

Sub Wait(Seconds As Int)
   Dim Ti As Long
   Ti = DateTime.Now + (Seconds * 1000)
   Do While DateTime.Now < Ti
   Loop
End Sub

Program started.
Initialized
Text --> QMODIÁ
I have received NAK