Problem with data flow from Fastrack Supreme

Legacy Open AT
1

When I open an ftp transfer connection it is locking the modem up to where it will not stream responses.

Here is a selection of my code:

Do
                buffer = ""
                localCom.DiscardInBuffer()
                localCom.WriteLine("AT+CREG?")
                System.Threading.Thread.Sleep(1000)
                If localCom.BytesToRead > 0 Then
                    buffer = buffer + localCom.ReadExisting
                End If
             Loop While Not buffer.Contains("+CREG: 0,5")
             buffer = ""
             localCom.DiscardInBuffer()

            Do
                localCom.WriteLine("AT+CGREG?")
                System.Threading.Thread.Sleep(1000)
                If localCom.BytesToRead > 0 Then
                    buffer = buffer + localCom.ReadExisting
                End If
            Loop While Not buffer.Contains("+CGREG: 0,5")

            buffer = ""
            localCom.DiscardInBuffer()
            localCom.WriteLine("AT+WIND=4")

            Do           
                If localCom.BytesToRead > 0 Then
                    buffer = buffer + localCom.ReadExisting
                End If
            Loop While Not buffer.Contains("OK")

            buffer = ""
            localCom.DiscardInBuffer()

            localCom.WriteLine("AT+WIPCFG=1")
            Do
                If localCom.BytesToRead > 0 Then
                    buffer = buffer + localCom.ReadExisting
                End If
            Loop While Not buffer.Contains("OK")

            buffer = ""
            localCom.DiscardInBuffer()
            localCom.WriteLine("AT+WIPBR=1,6")
 
           Do
                If localCom.BytesToRead > 0 Then
                    buffer = buffer + localCom.ReadExisting
                End If
            Loop While Not buffer.Contains("OK")

            buffer = ""
            localCom.DiscardInBuffer()
            localCom.WriteLine("AT+WIPBR=2,6,11," & Chr(34) & "MYAPN" & Chr(34))

            Do
                If localCom.BytesToRead > 0 Then
                    buffer = buffer + localCom.ReadExisting
                End If
            Loop While Not buffer.Contains("OK")

            buffer = ""
            localCom.DiscardInBuffer()
            localCom.WriteLine("AT+WIPBR=4,6,0")
 
           Do
                If localCom.BytesToRead > 0 Then
                    buffer = buffer + localCom.ReadExisting
                End If
            Loop While Not buffer.Contains("OK")

            buffer = ""
            localCom.DiscardInBuffer()
            localCom.WriteLine("AT+WIPCREATE=4,1," & Chr(34) & "MYFTPSIGHT" & Chr(34) & ",21," & Chr(34) & "MYUSERNAME" & Chr(34) & "," & Chr(34) & "MYPASSWORD" & Chr(34))
 
           Do
                If localCom.BytesToRead > 0 Then
                    buffer = buffer + localCom.ReadExisting
                End If
            Loop While Not buffer.Contains("OK")

            buffer = ""
            localCom.DiscardInBuffer()
                localCom.WriteLine("AT+WIPOPT=4,1,2,40,1")
  
              Do
                    If localCom.BytesToRead > 0 Then
                        buffer = buffer + localCom.ReadExisting
                    End If
                Loop While Not buffer.Contains("OK")

                buffer = ""
                localCom.DiscardInBuffer()

            Try
                localCom.WriteLine("AT+WIPFILE=4,1,2," & Chr(34) & "./10kTest.txt" & Chr(34))
 
               Do
                    If localCom.BytesToRead > 0 Then
                        buffer = buffer + localCom.ReadExisting
                    End If
                    System.Threading.Thread.Sleep(500)
                Loop Until buffer.Contains("CONNECT")

                buffer = ""
                localCom.DiscardInBuffer()
               fileBuffer = fileReader.ReadToEnd
                chrBuffer = fileBuffer.ToCharArray()

                For Each chrbuff As Char In chrBuffer
                    Do
                        If localCom.CtsHolding = True Then
                            localCom.Write(chrbuff)
                            Exit Do
                        End If
                    Loop

                Next

                localCom.WriteLine(Chr(3))

                Do
                    System.Threading.Thread.Sleep(1000)
                    If localCom.BytesToRead > 0 Then
                        buffer = buffer + localCom.ReadExisting
                    End If
                 Loop While Not buffer.Contains("OK")
.......

Everything works great up until the localCom.WriteLine(“AT+WIPFILE=4,1,2,” & Chr(34) & “./10kTest2.txt” & Chr(34))
It returns “AT+WIPFILE=4,1,2,”./10kTest2.txt"
but nothing after that is ever foound in the serialPort Buffer.
(I ended up putting counters in the loops so they would execute through after I realized the commands were being processed by the modem)
Everything works out great the file gets transfered, I end this function by stoping the stack, closing the bearer, etc.
THEN when I open up HyperTerminal everything streams out, as if the CTS on the TE side was False.

I currently have AT+IFC=0,2 SO that I am able to check CTS from the Modem and don’t overflow the buffer. When I instead set the modem to AT+IFC=0,0
there is no problem. All data is streamed back from the modem, EXCEPT that I overflow the buffer in the modem, and lose some of the data in the stream from the TE side.

Has anyone else had this problem and what is the fix?