Empty wave file when recording a call

[Sirpyerre]

When I run the code a empty wave file is created but when finished the applications this file is deleted.
I'm using a modem HIRO V.92 Model: H50113.
This application i will to use for access control the guest to residents in a housing subdivision.
My code is:

 private void OnDial(object sender, EventArgs e)
        {
            TAddress addr = (TAddress) cbAddress.SelectedItem;
            LINEADDRESSTYPES addrType = (LINEADDRESSTYPES) cbDestinationType.SelectedItem;

            TAPIMEDIATYPES mediaType = TAPIMEDIATYPES.AUDIO;
            if (addr.QueryMediaType(TAPIMEDIATYPES.VIDEO))
                mediaType |= TAPIMEDIATYPES.VIDEO;

            try
            {
                addr.Open(mediaType);
            }
            catch (TapiException ex)
            {
                if (ex.ErrorCode == unchecked((int) 0x80040004))
                {
                    try
                    {
                        addr.Open(TAPIMEDIATYPES.DATAMODEM);
                    }
                    catch (Exception exception)
                    {
                        toolStripStatusLabel1.Text = exception.Message;
                    }

                }
                else
                {
                    toolStripStatusLabel1.Text = ex.Message;
                }
                
            }

            currCall = addr.CreateCall(textDestination.Text, addrType, mediaType);
            if (currCall != null)
            {
                try
                {
                    playBackTerminal = currCall.RequestTerminal(
                        TTerminal.FilePlaybackTerminal,
                        TAPIMEDIATYPES.AUDIO, TERMINAL_DIRECTION.TD_CAPTURE
                    );

                    if (playBackTerminal != null)
                    {
                        playBackTerminal.MediaPlayList = new string[] {PLAY_FILENAME};
                    }
                    else
                    {
                        MessageBox.Show("Failed to retrieve playback terminal.");
                    }
                    RecordConversation();
                }
                catch (TapiException ex)
                {
                    MessageBox.Show("On Dial: " + ex.Message);
                }

                try
                {
                    currCall.Connect(false);
                    toolStripStatusLabel1.Text = "Placing call";
                }
                catch (TapiException ex)
                {
                    toolStripStatusLabel1.Text = ex.Message;
                }
            }
        }

        private void RecordConversation()
        {
            if (currCall != null)
            {
                try
                {
                    recordTerminal = currCall.RequestTerminal(
                        TTerminal.FileRecordingTerminal,
                        TAPIMEDIATYPES.MULTITRACK,
                        TERMINAL_DIRECTION.TD_RENDER
                    );

                    if (recordTerminal != null)
                    {
                        recordTerminal.RecordFileName = "PETER-GRABACIÓN.wav";
                        currCall.SelectTerminalOnCall(recordTerminal);
                        recordTerminal.Start();
                    }
                    else
                    {
                        MessageBox.Show("Error al grabar");
                    }
                }
                catch (TapiException ex)
                {
                    MessageBox.Show(ex.ToString());
                }
            }
        }

Thank you in avanced.