TWAIN Direct specifies:
- a communication protocol
- a scanner language
- an image file format
Its driverless design supports direct image capture between an application and a scanner on a local area network or in the cloud.
Scanner support comes in three flavors:
- a limited legacy mode with existing TWAIN drivers that can be expanded to full feature support by a scanner vendor
- a sidecar solution that pairs a USB scanner with a small dedicated piece of hardware that advertises itself for connectivity with the TWAIN Local or TWAIN Cloud protocols
- a native solution when a scanner by itself, with no additional hardware is fully capable of supporting TWAIN Direct
The documentation is divided in to protocols and languages, and is sub-divided into user guides, reference guides, and certification tests. The user guides should be read in their entirety to best implement TWAIN Direct applications. The reference guides are used in concert with sample code and TWAIN Direct tasks to create solutions. The certification tests validate that solutions are designed to the specification.
The best document to start with is the TWAIN Direct Specification – User’s Guide. It provides a roadmap for developing TWAIN Direct scanners.