How can I find the VID and PID of a device on the other end of a USB-to-Serial adapter? - windows

I am attempting to connect to a weight-measuring scale using the following communication line: Laptop -> USB to DB-9 Serial adapter -> Scale. The problem I'm experiencing is that my laptop recognizes the adapter as the device on the COM port, thus when I check the VID and PID of the device, it gives me the IDs for the cable and not the scale. Is there some way to find the information for the device on the other end?
I am coding in Python using the PySerial library, but any general answer would be helpful. The adapter I'm using is a USB to UART PL2303 from Prolific Technology Inc. My OS is Windows 10.
I have tried connecting scales from multiple different brands using a USB-to-Serial adapter, and I get the same result. I haven't been able to establish a connection with any of them, with all queries to the scales not being responded to. Two such scales are the Sartorius Entris and the Mettler Toledo Excellence Plus.
EDIT: Responses are saying that serial devices do not have a VID or PID. In that case, how can I tell if a serial device is a certain device from a specific manufacturer? I'm trying to do this so I can recognize when a scale is plugged in and not some other device, using a Python program to communicate with the scale.

Serial devices dont have VID/PID pair.
In "historic" times PCs have two ports - parallel and serial (also known as RS-232). Serial devices are PnP devices, so dont need driver and because this no need VID/PID pair.
What scales are you used?
If industrial, is very possible that are based on RS-485 standard.


Is there an easy way to get low-level data from a Mac USB serial port, from devices that do not show up in the /dev/ directory?

What I want to achieve is that I plug in a device, for example a mouse, but in general any device that outputs serial data via USB, and then either screen it in terminal, or store it in a file and, if possible, use python to do things with it.
As a concrete example, let's say I want access to the data from a trackpad plugged into a USB port on a macbook. When I run /dev/{tty,cu}.* in terminal, I get a bunch of devices, but none of them is the one I want. When I run ioreg -p IOUSB -l -b | grep -E "#|PortNum|USB Serial Number", I see that the device is plugged in, at a specific address (i.e. #14200000), as well as <class AppleUSBDevice, id 0x100002c38, registered, matched, active, busy 0 (10 ms), retain 14> and "PortNum" = 2.
Yes, the device is plugged in, no it does not show up in /dev/{tty,cu}.*. I don't want to have to write a device driver, I have heard that it is not the easiest thing to do. Are there any solutions for accessing low-level data from devices that don't show up in the /dev/ directory?
Devices showing up as /dev/tty... and /dev/cu... are devices implementing the asynchronous serial data communication protocol derived from RS-232. There used to be dedicated serial ports on computers. Today on a Mac, they are usually connected via USB.
Few USB devices implement the serial protocol. Instead they implement the HID protocol (keyboard, mouse etc.), USB mass storage protocol (external drives of all kind), USB ECM (for network adapters) or a custom protocol. Except for the ones with a custom protocol, macOS provides device drivers for all of them.
USB isn't a simple serial communication. Instead, devices configure several endpoints. Each endpoint uses a separate communication channel. Even USB CDC ACM for RS-232 like communication uses three endpoints. In addition, USB devices can pretend to be several devices at once. This is call composite device.
My understanding is that you want to observe and record USB communication. The main approaches are:
Use Wireshark. It is well known for observing and recording network traffic but it can do the same for USB. Unfortunately, with the ever tighter security on macOS, it isn't so easy to set up and probably doesn't work on Apple Silicon Macs anymore.
Use a dedicated USB protocol analyzer. They are very powerful and start at about USD 300.

Ways to analyze unknown USB device?

I have a piece of equipment at work that has a USB output, that then requires to be connected to a specific USB-to-Ethernet adapter in order to send TCP packets. I am trying to cut the Ethernet adapter out of the equation, and connect the USB output directly to the computer.
A Windows machine does not detect hardware changes when it's connected, so I'm thinking about using a Ubuntu device since it might have better network tools.
What are the ways I can test the device to figure out what it actually is? Is it even possible to remove the adapter from the equation in this situation?
PS. The device is a very specific ECU used in cars. It is not something I can download drivers for. It also uses a Class C IP address.

Identify Windows USB Sounddevice by physical USB port connection

When I connect several USB audio devices using the default drivers I usually end up with some kind of friendly device description like "nn- USB Audio codec" or something else, so I have currently no unique property which refers to a specific hardware the e.g. manufacturer ID. I would like to ensure that in case of re-enumerating or replugging the hardware to a different port that my software will automatically identify the changed windows audio device which maps to this hardware. I there a possibility to gather further windows audio device information which can be used to determine the physical hardware ?
Maybe a little clarification is needed:
I have two or more USB audio devices, not necessarily same product or manufacturer. The audio connections have different purposes, so I want to ensure that I my software uses constantly the same physical audio devices for different tasks. This sometimes fails when a re-enumeration occurs ( sometimes without changing the physical USB port connections, it's a windows thing...)
Ideally I would distinguish them by an individual serial number, which usually is only available with storage devices. But what I can retrieve is the "physical" USB topology when I'm looking at the device with a tool such as USBDeview from Nir Sofer. There I have a property like "Hub 3, Port1". If I could map this to a sound device I get from audio audio api like "nn- USB Audio codec" as seen in the sound control panel I would be perfectly happy.
May be this[1] post helps here, but I still have to figure out how to get a USB Port <-> Windwos Sounddevice mapping.
[1]: Can the physical USB port be identified programatically for a device in Windows? "

Communications between Visual C++ and Arduino:

I have a Arduino app that needs to talk to my PC across the USB (Serial) connection. I have this bit of code that I lifted from the Arduino Playground at
this->serialPort1->PortName = "COM5"; // Replace with your COM port!
this->serialPort1->Write( "7" ); // In the future, you'll expand on this
// to write your custom data to the board
My question is how does one determine what COM port the Arduino USB cable is attached to?
There are several ways you can approach this.
The most obvious is that you simply make your application configurable and tell it which serial port to use. The port name should never change, unless you have other processes on your machine allocating virtual COM ports such as Bluetooth drivers.
A second option is that you can do what the Arduino app does and scan the serial ports on the system looking for the hardware. Since you are using the CLR, System.IO.Ports.SerialPort.GetPortNames() will give you a list of all the serial ports on the system. (You can also get this from the registry.) Then you can enumerate through them and check the status of the pins to see which serial ports have devices attached. You should probably include in your sketch a way to query the Arduino so that you can send it a command and have it give a fixed response. This would allow you to discern your application from other serial devices such as modems.
There is a third option which would involve figuring out where the FTDI driver stores its configuration information in the system/registry and going from there. This is a bit more involved, so I can't give any information on if this approach is even viable.

USB Debugging

I'm looking for a very specific USB device for debugging systems that may use USB but not with a regular computer (proprietary hardware). I want a device that has a USB host controller and two USB device connections. The device to be debugged is connected to the USB host controller and one of the device connections is connected to another device with it's own host controller on it. The the other device connection is connected to a pc. The point being that all USB data travelling through the device (from the device connected to the host controller to the device connected to the first device connection) is reported to the pc.
I'll happily write software to do the logging (in fact I want to) but I can't seem to find a board like this anywhere. Can anyone help?
I have an Ellisys USB analyser, which isn't exactly what you describe internally, but does sit between a peripheral and a host and use a separate PC to collect the data.
(i.e. it has two 'B' and one 'A' connectors on it.)
Excellent product, and very helpful company.
Sniffing the USB shouldn't be too hard if you have the right hardware. And that is the tricky question. I haven't seen anything that describes the USB breakout box that you want. However I can say that this is in the realm of the following two magazines:
Nuts and Volts
Circuit Cellar
If they don't have a USB breakout box project in their archives, then at least they will have advertisements for small cheap single board computers that would have multiple USB ports that you can use for buffering the signals and reporting it back to your PC.
Alternatively is it possible to just wire your PC up to the middle of your two devices and write a custom drive that echos data back and forth while sniffing off a stream for you?
Sorry for the long delay in my reply -- I checked out one of our USB developer's toolchain, and he uses a Beagle USB Sniffer. He seems happy with it.
You're looking for a USB device with two upstream outputs. I think according to the USB spec, this is not possible. You will have two USB hosts trying to send messages and control the USB devices at the same time.
What if you were to look for a device which allowed you to view the data going through a hub via something other than a usb output?
If you're building something custom, take a look at this USB chip site. The chips are programmable via a windows application. Once you define how you want it to operate, it's saved on an EPROM on the dev board ($30-$50).
Sorry if this isn't helpful!