Getting info on USB-Serial converter

Question

Hope you can help me on this. I have a serial device, this device will then be connected to a USB-Serial converter, then the converter will be connected to my PC's usb port. The system will add another COM port to the Device Manager. My question is, how can I possibly map the COM port number to the converter in C#? I can successfully enumerate available COM port in the system by doing the SerialPort.GetPortNames(), but not sure what COM port number this converter have.

thanks ar

Answer 1

You can usually get some decent info out of a WMI query, although it requires the device driver to cooperate. Most do afaik. Run a query on the Win32_SerialPort class. You can use the WMI Code Creator tool to experiment with the query and auto-generate the C# code you need.

Don't count on being able to auto-select the device. You'll need a config option to allow the user to select the port. You can display the info you got from the query to help her pick the right one. Or ask her to unplug the device and plug it back in, the added COM port should be the right one.

Answer 2

We solved this different ways for different applications. We used explicit configuration for an instance where we had exactly one device of a particular type, but it wasn't clear what COM port it was going to be assigned until the system was configured. In another case, we had one USB cable that broke out into a hub with a bunch of converters on it, so we probed all the COM ports we could open successfully to look for our devices of interest.

A couple caveats with USB/serial converters on Windows -- if your device is something like a GPS unit that sends out data whenever it's powered on, Windows might detect it as an old serial mouse if it's plugged in during boot. Also, plugging into a different USB port is likely to chew up an additional COM port number (as well as break any explicit configuration you've done).

Answer 3

You would have to look this up somewhere in the registry.

I can only assume this is a FTDI chip. If so, you may be able to get info from using their public API, which is included with the drivers.

If no other answers, I will check later tonite at home, as my JTAG debugger has the same chip.

Update:

Here is the registry key for my device's assigned COM port (under PortName )

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\USB\VID_0483&PID_5740\498C54823932\Device Parameters

I guess you can just enumerate thru the USB devices with the usbser driver.

Answer 4

When i had the same problem (RFID reader), I checked each port if there was any data. Probably it would be something in COM4 : COM9. I know that it's not the best solution, but i used it on mobile device where i am sure about my COM connections...

Maybe in your driver's *.ini file there is some information about COM number.

Answer 5

If you are using an FTDI based solution for the USB<-> serial conversion, you can use the FT_PROG utility which is available from the FTDI web site to assign custom VID:PID pairs to the converter, which you can then query to identify which adapter is assigned to which virtual port.

Alternatively, you can make use of the FTDIChip-ID which is unique for each chip, details on this including code samples are located here: http://ftdichip.com/Support/SoftwareExamples/FTDIChip-ID.htm