Twunk_32 allows 32-bit TWAIN client software to communicate with Twain_16.dll. TWAIN -not-for-profit organization that defines a standard software protocol and API for communication between software applications and image acquisition devices. Application Program Interface (API) -platform for building software applications that enable software developers to access various system resources/features without writing hardware-specific code. Dynamic Link Library (DLL) -files containing programing code that can be loaded/run when required to perform a function and can be shared/used by numerous programs.