Originally developed by Pixel Translations (PixTran), an ISIS (Image and Scanner Interface Specification) Driver is the defacto industry standard enterprise-level scanner driver interface that unites scanners with software applications.
The benefits of having an ISIS driver are scanner manufacturers include guaranteed compatibility with hundreds of commercial ISIS applications, and software developers are guaranteed compatibility with hundreds of scanners from many different manufacturers.
Don't expect to see ISIS Drivers for anything except higher-end scanners due to relatively high development costs. ISIS drivers are designed for production scanning environments that are not always user-friendly; instead, data throughput and post-scan processing are top considerations.
Looking for an ISIS Driver? Check with the scanner hardware manufacturer or software developer. Often they are available for little or no cost via these sources. Otherwise, plan to shell out some serious coin if you have to purchase one.