how to access usb device uisng qt

[jacek]

i want to trasfer data b/w two PCs through usb port.
i mean both pcs are connected via usb-to usb cable(both side of cable is usb male connector)

USB 2.0 standard doesn't allow this. There is a "On-The-Go" extension that is meant for mobile devices which introduces mini-AB receptables, but I doubt that a PC will have one.

(1) how to use usb port on fedora 6

Either use libusb or write a kernel module.

http://www.beyondlogic.org/usbnutshell/

[amit_pansuria]

Sir,
my actually requirement is given below.
there are 30 modems. each has seperate usb 2.0 port
i want to connect 30 usb modems with one server pc through usb port.which is running on fedoara 6 o.s.
my aim is write a application software which reads message from particularusb port of particular modem and send it to anothere modems through usb port of server pc.
now which h/w i have top used to connect usb 2.0 of modem to usb 2.0 of server pc.
and how to write that application . i mean how to configure usb to work under fedora-qt
amit

[high_flyer]

and how to write that application . i mean how to configure usb to work under fedora-qt

Jacek has answered your question.
You need to read how to program usb devices under linux.
Jacek provided you with good links to start with.
Using it with Qt is not an issue - since Qt will have nothing to do with the hardware.
Or, ask a more specific questions.
"How to write a USB device driver" is a bit out of the scope of this forum, or any forum.
For that there are tutorials, and howto's.
I would start with libusb docs.

[jacek]

there are 30 modems.

What are these modems exactly? Are these just normal modems you use for dial-up connections? If yes, then actually you don't have to bother with USB --- Linux will handle it for you.