A major distinguishing feature between NEMA TS-1 and TS-2 controllers is:

The correct choice highlights the significant difference in the data bus interface between NEMA TS-1 and TS-2 controllers. The TS-2 standard introduced advancements in communication protocols, allowing for more data management capabilities and improved real-time monitoring. This upgrade in the data bus enables TS-2 controllers to support advanced features such as remote programming and diagnostics, which were not effectively supported by TS-1 controllers.

This distinction is crucial for traffic signal technicians, as it directly impacts the implementation of signal timing plans and the ability to integrate with modern traffic management systems. Understanding this difference helps technicians to choose the right controller based on the required functionalities and technological capabilities of the traffic system being deployed.

While other aspects such as power requirements, number of outputs, and size may vary or evolve slightly between these controller types, the primary and most impactful advancement is indeed related to the data bus functionality and its capability to support enhanced data communication and processing.