This manual page describes the access of USB scanners over the sanei_usb interface. For point one and three of this list have a look at the backends' manual pages for details.
Currently USB access is only tested for Linux, FreeBSD and OpenBSD. For installation, also check the /usr/doc/sane-1.0.8/README.platform files.
For scanners with a USB interface, it may be necessary to edit the appropriate backend configuration file before using SANE for the first time. For most systems, the configuration file should list the name of the USB device file that the scanner is connected to (e.g., under Linux, /dev/usb/scanner0 or /dev/usbscanner0 is such a USB device, the device file for FreeBSD is e.g. /dev/uscanner0). Do not create a symlink from /dev/scanner to the USB device because this link is used by the SCSI backends. The scanner may be confused if it receives SCSI commands. For a detailed description of each backend's configuration file, please refer to the relevant backend manual page (e.g. sane-mustek_usb for Mustek USB scanners).
For Linux, there is an alternate way of specifying scanner devices. This alternate allows to identify scanners by the USB vendor and product numbers. The syntax for specifying a scanner in this way is:
where VENDOR is the USB vendor id, and PRODUCT is the USB product id of the scanner. Both ids are non-negative integer numbers in decimal or hexadecimal format. The correct values for these fields can be found by looking at the output of the command "cat /proc/bus/usb/devices/". This is an example of a config file line:
would have the effect that all USB devices in the system with a vendor id of 0x55f and a product id of 0x0006 would be probed and recognized by the backend. The same config line in decimal format looks like this:
When using a USB scanner, ensure that the access permissions for the USB device are set appropriately. We recommend to add a group "scanner" to /etc/group which contains all users that should have access to the scanner. The permission of the device should then be set to allow group read and write access. For example, if the scanner is at USB device /dev/usb/scanner0, then the following two commands would set the permission correctly: