FOUNDATION Fieldbus H1 is one of the FOUNDATION fieldbus protocol versions. FOUNDATION H1 (31.25 kbit/s) is a bi-directional communications protocol used for communications among field devices and to the control system. It utilizes either twisted pair, or fiber media to communicate between multiple nodes (devices) and the controller. The controller requires only one communication point to communicate with up to 32 nodes, this is a significant improvement over the standard 4-20 mA communication method which requires a separate connection point for each communication device on the controller system.