Category Archives: Communication Protocols

IEC 61850-3 Ethernet Switch: Requirements & Substation Use

Ethernet has become the backbone of modern power system automation. From protection relays and bay controllers to SCADA gateways and digital substations, Ethernet networks now carry time-critical protection traffic alongside operational and engineering data. However, substations are among the harshest environments in which communication equipment can be installed. High electromagnetic interference, wide temperature ranges, vibration, and electrical transients… Read More »

IEC 61850 MMS Port Number Explained: Why TCP Port 102 Is Used

IEC 61850 has become the global standard for substation communication systems, enabling interoperability between protection relays, bay controllers, SCADA systems, and engineering tools. At the heart of IEC 61850 client/server communication is MMS (Manufacturing Message Specification)—and one of the most searched questions is: What port number does IEC 61850 MMS use? This article provides a complete explanation of… Read More »

IEC 60870-5-104 Port Numbers Explained: TCP 2404 & Secure TLS Port 19998

IEC 60870-5-104, commonly called IEC 104, is a widely used communication protocol in power system SCADA networks. Because IEC 104 runs over TCP/IP, port numbers are a critical part of how devices communicate, how firewalls are configured, and how cybersecurity is enforced. This guide explains all IEC 60870-5-104 port numbers, with a clear focus on unsecured connections using… Read More »

IEC 61850 Control Models Explained (Direct, SBO, SBOwES)

IEC 61850 does not treat control operations as simple “write a value and hope it works.” Instead, it defines formal control models that describe how a command is issued, who is allowed to issue it, and how safety is guaranteed. These control models are one of the most important — and most misunderstood — parts of IEC 61850.… Read More »

DNP3 Event Classes Explained: How Class 0, 1, 2, and 3 Really Work in SCADA Systems

DNP3 (Distributed Network Protocol) is widely used in power systems, water utilities, and industrial SCADA systems. One of its most misunderstood features is the event class system. Many engineers assume that Class 1, 2, and 3 represent fixed priorities defined by the protocol. In reality, DNP3 works differently. This article explains what DNP3 event classes really are, how… Read More »

IEC 60870-5-104 Security Explained: TLS, IEC 62351 & IEC/TS 60870-5-7 Guide

IEC 60870-5-104 (IEC-104) is one of the most widely used telecontrol protocols in electrical power systems. It plays a central role in communication between substations, RTUs, and control centers, especially in transmission and distribution SCADA systems. IEC-104 is reliable, efficient, and well understood by utilities worldwide. However, when the protocol was originally designed, cybersecurity was not a primary… Read More »

IEC 61850 Data Types Explained: The Complete Practical Guide

Everything engineers need to know about Basic Types, Common Data Classes, and how they appear in GOOSE, Sampled Values, MMS, and SCL. IEC 61850 is much more than a communication protocol—it is a semantic language designed to describe protection, control, measurement, and automation inside modern substations. At the core of this language lies one essential concept: 👉 Every… Read More »

Modbus Data Types & Formats: How to Decode Register Values Correctly

Modbus is a simple protocol, but the values inside registers can be displayed in many different ways. A single 16-bit register can represent: The challenge is that the Modbus protocol never tells you how to interpret the number. Only the device’s documentation explains the meaning. To decode Modbus data correctly, engineers must understand the different data type formats… Read More »

Modbus TCP/IP Explained: Complete Beginner-to-Expert Guide

Modbus TCP/IP is one of the most widely adopted methods for connecting industrial devices over Ethernet networks. It is used in factories, power plants, water treatment facilities, building automation systems, and countless other fields where equipment must exchange information reliably. Even though modern automation protocols offer advanced features, Modbus TCP/IP remains extremely common because it is easy to… Read More »

IEC 61850 Sampled Values (SV) Explained: A Simple Technical Guide for Digital Substations

Sampled Values (SV) are one of the core technologies behind modern IEC 61850 digital substations. They allow current and voltage measurements from CTs and VTs to be transmitted as digital Ethernet messages instead of analog signals over copper wires. If GOOSE replaces binary wiring, Sampled Values replace CT/VT analog wiring. This article explains how SV works, why it… Read More »