does it exist a way to create a COM port based on a VXI serial port instrument

[jmv 60]

The goal is to be able to access a serial port located in a VXI instrument either through VISA ASRL device or through Windows API (createfile, writefile, readfile)functions

[Dan_Mondrik]

If Windows saw your VXI device's serial port as a native serial port, then VISA would detect it automatically as well. But that isn't the case and I don't think there's any way you can make that happen.

Your best bet is to find an instrument driver for your VXI device and use the API they provide. Once you open the device, their API will probably provide similar functionality to what the VISA API provides, though it might look different.

Dan Mondrik
National Instruments

[jmv 60]

Thank you for your answer but The problem is how to do to make the VXI device's serial port seen as a COMx port by Windows. So If you have any idea to do that I would really be very interrested. About the VXI device We have developped an API with several functions like Open_Port, Close_Port, set_port, receive_port, send_port, reset_port which can be called from a C application. These functions are included in a DLL

[Dan_Mondrik]

It's just not feasible. Windows requires a kernel driver for Serial ports, and you couldn't implement your VXI accesses in the kernel because we don't provide kernel-level APIs to you. NI-VXI and NI-VISA are user-level APIs only.

If you absolutely must do this, note that I said it is not feasible - but it is possible. You'd have to have your kernel driver call out to another user-level process that in turn made VISA calls. This has been done before, both at NI and elsewhere, and I highly discourage it because it's extremely error-prone and you're too likely to get blue screens. A kernel driver just is not meant to make calls back out to the user level.

Dan Mondrik

[jmv 60]

Thank you Dan for all of these information
It will help me to make the best choice
Jean-Michel