TWAIN SANE (http://www.ellert.se/twain-sane/): "This is a TWAIN datasource for MacOS X that aquires images using the SANE backend libraries. The SANE backend libraries provide access to a large range of scanners connected through SCSI or USB. For a complete list see the documentation on the SANE project homepage. It works with my HP SCSI scanner, and many people have reported success with a large number of different scanners. The feedback from users have helped the SANE developers to fix problems with various backends, so with each release of the SANE backends more of the MacOS X specific problems have been solved."

TWAIN SANE -- which is free -- enabled my old but reliable Umax Astra 1220S scanner (with a Belkin F5U541 SCSI to FireWire Adapter) to work brilliantly with Readiris Pro 11 OCR software on my PowerMac G5.

Download the TWAIN SANE installers and install in this order:

1 - libusb

2 - sane-backends

3 - TWIAN-SANE

Highly recommended!