Edgent applications interface with other entities by way of a connector. The other entity may be an IO device, an IoT messaging hub, a file, process, database, another Edgent application/topology, etc.
Edgent includes several connectors -- see the "Edgent Connectors" package group in the javadoc. The CommandStreams connector can be particularly useful if commands already exist for getting data to or from an entity.
When your application needs something new or special Writing Connectors for Edgent Applications tells you what you need to know!