Not getting data back from a serial device

General
1

Hi All.

I am trying to get a serial connection running, and as far as I can tell I have it properly done. I can see my serial device, and this is confirmed as it disappears when I remove the connection, and re-appears when I attach it.

With a button I have created I went to send data in my textfield to the unit, and when I do so I see the indicator flash, however I never get any data in my textArea.

Here is my button code:

        SerialConnection1.Connect
        SerialConnection1.Parity = SerialConnection.Parities.Odd
        SerialConnection1.Baud = SerialConnection.Baud9600
        SerialConnection1.Write(TextField1.text)

and here is my data received code within my serialConnection1

Var data As String
data = Me.LookAhead
If data.IndexOf(EndOfLine.Windows) > -1 Then
  TextArea1.Value = TextArea1.Value + Me.ReadAll
End If

Any ideas where I can look for why?

Regards

2

are you sure your device sends an endofline.windows ?
what happens if you remove the line
If data.IndexOf(EndOfLine.Windows) > -1 Then

3

may be better… only :

  TextArea1.Value = TextArea1.Value + Me.ReadAll

also take care of the encodings of the incoming string ?

4

Hi Jean-Yves

Yeah, tried that. I can see the data going to my usb modem, but I get nothing back!
I’ve looked through examples but don’t see any examples for serialConnections. Does anyone have an example they would like to share?

Regards

5

do you get something back from the device if you use a serial terminal app ?

6

Hi Jean-Yves.

When I connect with the Mac Terminal Program, I get a response to various AT commands.

But interestingly, when I physically connected the USB modem to my Mac, I now get an error when I try to connect. “Access denied”

Here is the code that worked with another serial device

Sub Action()
  If Me.Caption = "Disconnect" Then // Disconnect from the serial device
    SerialConnection1.Close
    Me.Caption = "Connect"
    DevicesPopupMenu.Enabled = True
    DeviceListUpdater.RunMode = Timer.RunModes.Multiple 'turn it on
  Else // Connect to the serial device
    // Set the serial device to the index of the one chosen in the popup menu
    SerialConnection1.Device = SerialDevice.At(DevicesPopupMenu.SelectedRowIndex)
    Try
      SerialConnection1.Connect --> this is where I get the access denied Error 100
      DevicesPopupMenu.Enabled = False
      DeviceListUpdater.RunMode = Timer.RunModes.Off
      Me.Caption = "Disconnect"
    Catch error As IOException
      Beep
      MessageBox("The selected serial device could not be opened.")
    End Try
  End If
End Sub

Update: I loaded the drivers (newest ones) for the usr Robotics 56k Modem and now I can connect.
I still don’t get a response displayed when I send an ATH command, even though I get a response from the modem with a terminal command.

Regards