libusb
is an open-source userland USB
API/library that enables an application to
access USB devices. libusb has been
implemented for a number of operating environments, including
Linux, BSD, MacOS, and Windows, as well as for Oracle Solaris and Sun
Ray environments.
libusb applications can run on any operating environment that supports
libusb. For further information, see
/usr/sfw/share/doc/libusb/libusb.txt
or the
libusbut
man page.
There are some open source applications that make use of libusb support and enable users to access devices, such as the SANE project (http://www.sane-project.org/) for scanners. To find more open source applications, see http://sourceforge.net.