Eccouncil Exam ICS-SCADA Topic 8 Question 30 Discussion

Modbus RTU (Remote Terminal Unit) is a communication protocol based on a master-slave architecture that uses serial communication. It is one of the earliest communication protocols developed for devices connected over serial lines. Modbus RTU packets are transmitted in a binary format over serial lines such as RS-485 or RS-232. Reference:

Modbus Organization, 'MODBUS over Serial Line Specification and Implementation Guide V1.02'.