Well, I solved this. All necessary info is in this [](<a href=)very long thread[^]"] over at HP forum.

Completely agree. I just was trying to find out if the main part of his problem was using the IDE or taking care of "logistics" such as includes or language syntax. But it seems that he was able to write a good solution with your help, so you were right. Cheers, Gary

Yes and by your other post it seems you do indeed have a program! Nice job!

He's saying "I have no idea how to write a program." In this case, I would imagine the parts for "include headers" and "declare variables" are going to come hard to him, maybe even be the most difficult part. Perhaps he already understands the math required, possibly... I would ask a couple of questions: What language are you using? What in the world book is it that you are using, that you read it six times and don't know how to write a program...is this more of a problem of finding and/or using the IDE? (tools to create the program)? Are there any options available of someone for you to sit down with and be shown firsthand how to get started? This may not be a problem that can be solved over a forum... Have you explained your situation to the instructor, if there is one? This is step #1, in my experience, just open that communication line and let him/her/them know you're having trouble and what the trouble is exactly.

no reply on this one huh? Yeah, it seems to be a toughie...well just wanted to add some info I think I left out: I'm using file-based access to the port to achieve the communication. I call SetupDiGetDeviceInterfaceDetail to get the device path, and use ReadFile and WriteFile from there on. So the problem is getting some piece of information from the SetupDi functions (or maybe CM_ functions) that I can match with something that I get from the spooler functions (OpenPrinter, GetPrinter, etc.) The SetupDi functions only give me manufacturer name, model, and serial #. As I tried to say above, the options as I see them are: 1 retrieve serial # from spooler functions (I can get it from the other side) 2 match virtual USB port in spooler (ie "USB0001") to actual port (maybe "hub#:port#", but any format will do) <-seems more likely option Just wanted to make sure I was being as clear as possible. Thanks!

Hi! I need to implement bidirectional communication with a USB printer. Short story is: there can be more than one printer of the same model connected to the system at a time. I may have access to the serial numbers of the printers through the device ID (not even sure of this yet), but I need to match this up with the "friendly name" used in the spooler to be sure that I have the right printer. I also have a sort of virtual port number obtained from the registry, but that seems to be completely irrelevant. Does anyone have any ideas how to do this? The unmodified driver (we are an OEM) cannot tell identical printers apart from the driver level, so I don't even know if this is possible. Obviously the spooler knows the difference, but the spooler interface (WritePrinter, ReadPrinter) is not bidirectional-capable in this driver. Thanks much...

I am certainly in the "no clear understanding" category. WinFX extensions what? I'll have to go read up on that. I'm currently trying to claw my way into gaining some experience with .NET framework 1.1 (it's tough at my company, we don't have enough developers and we're mostly mired in maintenance), but I didn't know that there were multiple version numbers that we need to worry about now. I thought it was bad enough that users need a .NET Framework in order to run our product.