PPPSerialModem crashes when trying CellularModem sample

NETMF & Gadgeteer
1

Hi, I’ve got a Cerberus 1.3 upgraded to firmware 4.3.7.10. I’m trying to use the CellularRadio to connect to the internet, using the sample in the product description. Because it throws an unknown exception in the call to cellularRadio.UseThisNetworkInterface, I’ve downloaded the CellularRadio from BitBucket and have determined that the throw is when the PPPSerialModem object is created. At this stage I’m stumped. Can anybody suggest how to move forward?
PS: Is it correct that all GHI modules are version 4.3.7.10, but Microsoft.SPOT and System assemblies are version 4.3.1.0 ? Or do I need to download something else?

2

Further to this, the stack trace upon the exception being thrown when constructing PPPSerialModem shows:
GHI.Networking.BaseInterface::NativeConstructor
GHI.Networking.BaseInterface::OnConstructed
GHI.Networking.PPPSerialModem::.ctor
Gadgeteer.Modules.GHIElectronics.CellularRadio::UseThisNetworkInterface
Gadgeteer.Modules.GHIElectronics.CellularRadio::UseThisNetworkInterface
Gadgeteer2015.Program::b__2

And the exception message is: Exception was thrown: System.Exception. The VS debugger showed the following message: An exception of type ‘System.Exception’ occurred in GHI.Networking.dll and wasn’t handled before a managed/native boundary.

Help!

3

What kind of modem are you using?

There are a number of threads on PPP issues, this one may be informative.

https://www.ghielectronics.com/community/forum/topic?id=19670&page=1

4

I did a cellular version of a Connect The Dots device here https://github.com/Azure/connectthedots/tree/master/Devices/DirectlyConnectedDevices/NETMF/ConnectTheDotsGadgeteer and I know it worked with Rogers in Calgary. I used a Spider board as I did a wifi, Ethernet and cellular version of the device, but the code should be about the same.

5

@ PHITEK - The hardware in use is a Cerberus mainboard, a USBClientDP for power, a RS232 for serial in and the Seeed SIM900 cellular modem, all from the GHI catalog.

6

It’s frustrating that I can’t even create the PPPSerialModem object, as the similar threads talk about debugging the interaction between modem and PPP, but I’m just trying to get the object going. I simplified the program down to a few lines, with the same result - creating the PPPSerialModem object throws an exception.

using System;
using Microsoft.SPOT;
using System.IO.Ports;

namespace ppptest
{
  public class Program
  {
    public static void Main()
    {
      SerialPort s = new SerialPort("COM2", 19200, Parity.None, 8, StopBits.None);
      s.Open();
      try
      {
        var xyz = new GHI.Networking.PPPSerialModem(s);
      }
      catch (Exception ex)
      {
        Debug.Print("Exception: " + ex.Message);
      }
    }
  }
}
7

Correct, no PPP on Cerberus.

8

Thank you for pointing this out. I’ve ordered the spider II.