USB stands for Universal Serial Bus . See http://www.usb.org/ for information about USB.
Tom Wilkason seems to be successful teaching Tcl to send data through USB ports [L1 ], as was Uwe Klein, with a SWIGified libusb ...
UK the google newslink leads me down a dark alley;-?. I've put a swig of my libusb effort on the net: http://home.foni.net/~kuttersegeln/swig_libusb-20050616.tgz
See also Serial Port for an opportunity to access USB via a virtual com port driver. -- RJM