Is it possible to communicate directly over USB?

Question

Is it possible to have two applications on the same computer to talk to each other directly over USB (no cable, no associated devices)? Is it easy/hard? What API would you guys recommend?

Yes, I posted a similar thread, but it was asking specifically for a JAVA/USB implementation, which I found, but I need windows support. So now I'm looking for any USB API - it doesn't have to work in java. I can always just use JNI/JNative to use the native code/library.

I haven't found many people on the internet that have done the same thing.

Answer 1

If you are just looking to allow two processes to communicate, you could use Unix or Domain sockets. I can't think of a situation where interprocess communication over USB locally would be an advantage. Java has very good support for doing this.

Answer 2

No Cable and/or no Devices

So what you are asking then is not possible (or even make any sense) it would be like asking how can 2 apps talk via serial ports with nothing connected..

Perhaps you could try and find out what the actual end aim is, if its just interprocess communication ther are many different ways to skin that cat...(com, wcf, memory mapped files etc etc)

Answer 3

Communications over USB necessarily involves electrical connections and pull-up resistors and particular voltages appearing on particular lines at particular times. These are all pretty hard to simulate without an actual cable.

Jan Axelson's USB Central is a great place to start to learn about USB communications.

Answer 4

The USB "Bus" is the wire. USB is NOT for interprocess or even peer-to-peer communications. It is solely for communication between a host and a peripheral over a cable where the host initiates any/all traffic. You cannot (normally) connect 2 hosts together, nor two devices together, or have any sort of symmetrical communication between a host/device.

If you ONLY want inter-process communication between two process on the same machine, USB is NOT the way to go. It is completely non-sensical. If you want inter-process communication between two process on two different machines, you should use TCP/IP.

If you are to developing a USB device and want to develop the host and device software before any prototype hardware is ready, and what you are REALLY after is some development or simulation environment where you can do that on the same machine, hook them up, and test it, that is an entirely different thing.

Answer 5

I guess with a lot of kernel work you might get something like this to work. There is an existing product that can transfer usb other network. So i guess it simulate usb host controller or something similar. If you can simulate host controller you can simulate actual device connected to this controller. And let the user mode application to control this device.
But i would estimate it as an at least 6 MM project for experienced kernel programmer with deep understanding of USB protocol in additional.
And the main question is why ? I can't find any logical reason for this use case (does not mean that it's not exists).