Cadcorp VARs can write their own Plug-in Datasets for file formats not supported in the core Cadcorp SIS Desktop 9.
Plug-in Datasets are seamlessly integrated into the SIS User Interface, e.g. Overlay
Plug-in Data Sources are a special kind of Plug-in Dataset which does not use a single file (or related files) but could instead read graphics from a database.
TIP: See Dataset Formats for a list of available built-in Datasets, Plug-in Datasets, Plug-in Image Servers and Plug-in Data Sources.