Which year was the Modbus protocol developed?

The Modbus protocol was developed in 1979, making that the correct answer. Initially created by Modicon to facilitate communication among their programmable logic controllers (PLCs), Modbus was designed to be an open and simple communication protocol that could be utilized on a wide range of devices. Its significance lies in its ability to provide a standard, easy-to-implement methodology that has had a lasting impact on industrial automation and communication systems. The implementation of Modbus has played a crucial role in the interoperability of devices from different manufacturers within industrial environments, contributing to more efficient operations.