IMS Connect

I am trying to create a simple TCP program to interact with IMS Connect on a mainframe (please see code). At this point, I'm just trying to verify that I am getting to IMS Connect on the mainframe.

The program is copied from a Microsoft example and works fine when interacting with a localhost server on the same machine. However, when going against the mainframe and IMS Connect, it hangs on the "networkStream.Read(bytes, 0, CInt(tcpClient.ReceiveBufferSize))" line. I am expecting a message from the mainframe saying that the input is invalid (this isn't a message recognizable to IMS Connect yet), but I seem to get no response.

Any suggestions would be appreciated, but please keep them as simple as possible.

Thanks,
John

vb.net Code:

Imports System.Net.Sockets   
Imports System.Text   
  
Class CTestTCPClient   
    Shared Sub Main()   
        Dim strHostName As String = "xxx.xxx.xxx.xxx"  
         Dim intPortNumber As Int32 = 9999   
        Dim tcpClient As New System.Net.Sockets.TcpClient   
        tcpClient.Connect(strHostName, intPortNumber)   
        Dim networkStream As NetworkStream = tcpClient.GetStream()   
        If networkStream.CanWrite And networkStream.CanRead Then  
            Dim sendBytes As [Byte]() = Encoding.ASCII.GetBytes("Is anybody listening...")   
            networkStream.Write(sendBytes, 0, sendBytes.Length)   
            ' Read the NetworkStream into a byte buffer.   
              Dim bytes(tcpClient.ReceiveBufferSize) As Byte  
            Console.WriteLine("About to get buffer size")   
 
            ' It hangs on this line:   
  
            networkStream.Read(bytes, 0, CInt(tcpClient.ReceiveBufferSize))   
  
            ' Output the data received from the host to the console.   
            Dim returndata As String = Encoding.ASCII.GetString(bytes)   
            Console.WriteLine(("TCP Server returned: " + returndata))   
        Else  
            If Not networkStream.CanRead Then  
                Console.WriteLine("Could not write data to data stream")   
                tcpClient.Close()   
            Else  
                If Not networkStream.CanWrite Then  
                    Console.WriteLine("Could not read data from data stream")   
                    tcpClient.Close()   
                End If  
            End If  
        End If  
        ' Pause to let the user view the console output.   
        Console.ReadLine()   
    End Sub  
End Class