A data source, or TWAIN source, file provides information about the source device (for example, scanner) to the TWAIN-compliant application. It also provides the user interface for the source device in the application, and can serve as a driver for the source device. Data source files can even perform specific operations (for example, prescan the scanner bed). While most applications use the user interface provided by the data source file, the TWAIN specification enables applications to use their own interfaces instead.
Most source devices acquire raster, or bitmap, image data. However, TWAIN-compliant devices can acquire other data types from both peripheral and virtual devices (for example, image databases, digital cameras). You can either connect a TWAIN-compliant device directly to the host computer using a SCSI or serial connection, or connect it remotely using a network.
In Windows, the Source Manager searches for data source files (*.ds) in the Twain or Twain_32 folder, which is usually in the Windows folder. In Mac OS, the Source Manager looks for data source files in the System Folder:Preferences:Twain folder. However, many Mac OS source devices use application plug-ins that follow protocols different from TWAIN. For more information, contact the device manufacturer.