I'm trying the Microsoft sample for Serial Port and it's working on Raspberry Pi2 but not on local machine , on,local machine return null.
the DeviceCapability already added, that's why it's working on Pi2.
any idea why it's not working on local machine
local system:
Win10 Ent.
VS 2015.3
I found this answer :(
Link
System-internal or on-chassis serial ports may be enumerated by DeviceInformation.FindAllAsync(), but cannot be opened by SerialDevice.FromIdAsync() because they currently are not supported. However, serial ports connected over USB, such as on USB-to-Serial cables are supported.
Update :
the issue still there even after the updates untill now
Serial ports marked as internal to the machine
(DEVPKEY_Device_InLocalMachineContainer == TRUE) are not accessible
unless explictly marked by the vendor driver as unrestricted
(DEVPKEY_DeviceInterface_Restricted == TRUE). Devices connect via most
PCI COM port expansion cards are therefore not accessible.
Inaccessible serial ports may still be enumerated by
DeviceInformation.FindAllAsync(), but cannot be opened by
SerialDevice.FromIdAsync(). Attemping to open such a device will
either throw an exception or return null. Apps should handle this case
by filtering such serial ports from the user's view, so that the user
will not be able to interact with such an unsupported serial port.
Related
Currently I have a server, that communicates with a projector through a RS232. The server opens a com port when the projector is connected. The same happens to any PC when a certain type of device is connected through the USB (lets say an Arduino for example). What I want to do it basically replace the projector with a PC/Arduino/Raspberry without the server noticing anything. That would mean the server will recognise the connected PC and open a COM port for it. What do I need to do on the PC so that it automatically opens a com port on the server? I guess there is something very basic that any printer, Arduino, projector etc does, that computers recognise it as a "com port device".
P.S. Doesn't matter the OS on the PC, I just need to make it work and then implement w/e I need to do with the established communication over the port.
P.S.2 I've searched a lot about it, but probabl I am doing it wrong, because I didn't find my type of question anywhere.
COM ports are basically hardware that is detected by the system. Let's say, if an Arduino is connected to a PC, it has its onboard USB to TTL converter which can be found in the device manager(if using windows). Similar USB to TTL converters are there in the market like CP2102, PL2303 which acts like a COM port even if no device is connected further to it. it may be possible that the program you are using(as you referred server) may be sending some data over the serial port and verifying the hardware.
What you need to do to replace it is, first of all, find the baud rate at which the communication is going on, then, listen over the serial lines which machine is sending which message in the sequence(there must be a handshake as I mentioned earlier), if a complicated algorithm is not used by the device, you can simply mimic the device by sending same messages over serial.
I seem to only be able to access physical ports. I do want to access virtual ones like ones created with virtual null modem or virtual serial port driver.
Does anyone know if this is possible.
Chrome enumerates serial ports by calling SetupDiGetClassDevs with GUID_DEVINTERFACE_SERENUM_BUS_ENUMERATOR. As I discovered when implementing this enumeration logic there are a surprisingly large number of ways to ask Windows for a list of all available COM ports. The advantage of this approach being that it provides device information which can be used to get the human-readable name of the device and USB product identifiers if it is a USB device. It is likely that a virtual COM port driver may be creating the device in a way which prevents it from being discovered this way.
I've created https://bugs.chromium.org/p/chromium/issues/detail?id=1238369 to track this as a Chrome bug. Please comment on whether you are using a different virtual serial port driver than the one mentioned there.
I managed to get Chrome to see the virtual serial ports using com0com on Windows 10 21H1 (OS Build 19043.1110). Chrome connects to the port successfully and it works as expected:
Hi! Asked this question on many forums and nobody could answer me so PLEASE help!
I have Android device connected to Linux device via USB tethering.
On Android device I have front-end(html, js, css) browser app and on Linux device I have back-end(node.js).
There is a socket connection between front-end and back-end with defined IP:PORT.
Androids gateway is Linux device. Linux device is connected to local network.
When Android device is connected to Linux device, Linux device initializes new network interface called usb0 with static IP address.
Sockets are based on that network IP that is same on every instance of front-end+back-end devices.
I have more than 5 instances of same front-end+back-end devices connected to local network.
Is there a way to somehow find the back-end device IP address without setting it static?
My problem starts when starting all devices at the same time. Sometimes Android device in instance 1 connects to Linux device from other instance and I want to prevent that by not connection to usb0 with Android but to eth0 DHCP of Linux device. I can never know which IP address will be on Linux device but front-end app needs a IP:PORT to connect.
PORT is defined so the string for connecting is {IP + ":3000"}
I know I can see all the IP addresses on network with arp or similar but I need to do that automatic in front-end app on app start up.
I want to find first device IP address that android device is connected to. That is always a front-ends pair Linux device.
Or if it is not possible to prevent Android device to be able to connect another instance with IP tables on Linux device.
P.S I know that Android is also Linux but someone who wants to answer will know what I'm talking about.
Here is a solution describing how to listen for tethering state changes:
First you need to be familiar with BroadcastReceiver. You can find a lot of tutorials describing in great detail how this works (try googling how to listen for connectivity changes in Android).
In order to get the Tethering state update, you need to use a hidden filter action of Android (see ConnectivityManager) and in your BroadcastReceiver class:
IntentFilter filter = new IntentFilter("android.net.conn.TETHER_STATE_CHANGED");
then register the filter to your BroadcastReceiver:
myApplicationContext.registerReceiver(this, filter);
In your onReceive(final Context context, final Intent intent) method, the Intent.extras information contains 3 arrays filled with the corresponding tethered network interface:
erroredArray / availableArray / activeArray
It's a little bit tricky but you can get the tethering status information.
In addition, you can do some reflexion on a hidden function of Android code:
Search for getTetherableIfaces() in the Connectivity Manager.
Here is a link: https://github.com/android/platform_frameworks_base/blob/master/core/java/android/net/ConnectivityManager.java#L1604
I am working with someone using Mbed and a LPCXpresso11U68 board.
I'm not intimately familiar with this particular board, but it has two USB connectors on it, one for the OpenSDA-ish debugger, and a second one is a direct connect to the CPU. I can connect both of these ports to my PC and attach a terminal emulator to each of them, and both ports show output (with a small installed program running on the board).
The device manager shows me that one port (COM51) is using "mbed Serial Port" driver and the other port (COM52) is using "Mbed Virtual Serial Port.
So far so good...
There is a reset button on the board. If I press that button, the port that is attached to the PC using the Mbed Virtual Serial Port driver (in my case COM52) stops operating. The other port (COM51) just restarts cleanly.
The problem I'm having is that after I exit the terminal program (note this happens with both TeraTerm and uCon), if I attempt to reconnect to that port, its not in the list of available comports. Strangely thought, it is still present in the Device Manager.
The only way I've found that I can clear this problem is to unplug/plug that usb cable (COM52) or issue a BREAK condition to COM51 (which AFAIK, resets the board).
I am the writer of uCon and I'd like to be able to detect this (which I can), and also be able to restart the comport connection without any other manual intervention.
One final note: apparently this is not specific to the LPCXpresso11U68 board; my guess it is some issue with the Mbed Virtual Serial Port driver.
Anyone have a clue what may be going on here?
I've an application that uses GSM commands sent over a serial port to a GSM ModeM.
The application works just fine on Windows XP, 7 etc., but sometimes it does not connect to the serial port on Windows Server 2008.
I tried to check using an application called Tera Term, but when I try and connect it to the port where the ModeM is supposed to be connected to, I get an error saying the COM1 port is not available ( it is the required port ).
This could indicate that the COM port is busy or occupied...and indeed when I try to rename the port, I get a Windows Warning that port is opened by some other application and renaming it can have consequences etc.etc...
How do I find out which, if any, application is using the COM port? I tried Portmon, but it remains greyed out in the Ports/capture area...so I cannot use it to find out what's happening with it?
Could anyone please tell me if there's a problem with the COM port detection in Windows Server 2008? Or if it's a problem with Tera Term/ PortMon that they're not able to detect the COM port?
This issue is baffling..kindly help me on this.
Thanks...
I think you should be able to use Process Monitor to find out which application is opening or accessing the COM1 serial port, or at least figure out what is going on. It has been while since I last had to do this so I don't remember the details of how to go about doing that.
If you decide to do this, I recommend running Process Monitor on a system that you are able to get this to work successfully first. That way you can see what a "normal" system looks like and compare it to what you are getting on the Windows Server 2008 system.