TWAIN seems to be an acronym but it is not know exactly what it is supposed to mean. Some have called it "Technology Without An Interesting Name." TWAIN was created in 1991 by a group of hardware and software companies who's goal was to provide an standard way to interconnect raster input devices with applications.
 Input Devices
Input devices include:
- Scanners of all types
- Digital Cameras
- Imaging Databases
Applications require a specific implementation to be TWAIN compliant.
- Image viewers
- FAX applications
- Word Processors
- OCR software
- any application supporting images.
 OS connection
Originally Microsoft worked together with the TWAIN working group to establish that the interface would be owned and supported by the OS. Support was first shipped in Windows98. This decision has restricted the proliferation of this standard to only include Windows platforms but that seems to be changing in version 2.0.
The latest standard is version 2.0 approved in February 2008 and finally released in November. It has support on Windows and Mac OS's. Recently Kodak announced support for Linux. IBM has a version for OS/2.
 Similar competing systems
- WIA, Windows Image Acquisition, is a windows interface for scanners and video devices.
- SANE, Scanner Access Now Easy, is an API that provides standardized access to any raster image scanner hardware (flatbed scanner, handheld scanner, video- and still-cameras, frame grabbers, etc.). The SANE API is public domain. It is commonly used on Linux.
 For more information
http://www.twain.org/ - The twain working group.