1 Introduction

In long distance RS-485 systems the need to find cost effective solutions without risking performance is paramount to a successful system design. TI’s Powerbus devices, the THVD8000 and THVD8010, tackle this issue by using OOK modulation of RS-485 and an external coupling network to allow data and power to share the same bus. However due to the nature of Classical RS-485 against Powerbus neither device can properly understand each other preventing communication between Classical RS-485 and Powerbus.

This presents a problem in large systems where the designer may not have control of every communication node connected to the bus and can cause the designer to fall back on Classical RS-485 to ensure compatibility in all of their systems. However combined solutions can exist to allow one board to be designed for multiple systems – Powerbus or not. This note will first cover what Powerbus is and how it works. Next it will delve into the differences between Powerbus and Classical RS-485 analyzing where the incompatibility lies. Finally, a look into a joint solution that can be applied into varied systems.