Modbus is a de facto standard for industrial communication which supports both serial- and TCP/IP-based communication. The core of the protocol consists of a function code (read or write) and data (what to read, what to write). Different packet forms are used, depending on the underlying bus, but that core set of information does not change.

This library allows for low-level access to that core function set and provides an API which includes both master (client) and slave device (server) functionality.