Zakaria El Intissar

I'm an automation and industrial computing engineer with 12 years of experience in power system automation, SCADA communication protocols, and electrical protection. I build tools and write guides for Modbus, DNP3, IEC 101/103/104, and IEC 61850 on ScadaProtocols.com to help engineers decode, analyze, and troubleshoot real industrial communication systems.

Author Archives: Zakaria El Intissar

IEC 61850 MMS Explained: Full Guide to Reporting, Control, and Communication in Digital Substations

IEC 61850 is the modern communication standard used in power utility automation systems. It defines how intelligent electronic devices (IEDs) communicate inside substations and across modern electrical networks. One of the most important technologies inside this standard is MMS (Manufacturing Message Specification). MMS is used for supervisory communication, real-time monitoring, remote control, reporting, configuration, file exchange, and system… Read More »

IEC 61850 Explained: Why It’s Not a Protocol but a Complete Substation Engineering Language

When people first hear about IEC 61850, they often assume it is simply another communication protocol like DNP3, Modbus, or IEC 60870-5-104. But this assumption is incorrect. IEC 61850 is not just a protocol—it is a full engineering language designed to describe, model, and structure the functions that make up modern digital substations and power automation systems. Where… Read More »

DNP3 vs IEC 61850: Full Technical Comparison of SCADA and Digital Substation Protocols

DNP3-IP, designed for distribution SCADA and remote telemetry, and IEC 61850, built for advanced substation automation and high-speed protection schemes, represent two fundamentally different communication approaches in modern power systems. Modern electric power systems depend on digital communication networks that connect substations, field devices, control centers, and automation systems. Two of the most important communication standards in this… Read More »

Instant IEC 101 Decoder – Paste Any IEC 101 Hex Frame, Get Clear Results

Looking for a quick, hassle-free way to decode IEC 101 frames? This free IEC 101 Decoder runs entirely in your browser and turns raw hex into clear, readable text instantly. No installs, no setup, no extra tools. Just paste your data and get answers. It also handles originator addresses and can automatically tell whether your frame uses a… Read More »

Modbus TCP/IP Port 502 (IANA Default Port) — Simple Guide for Real Industrial Systems

In almost every industrial plant today, you’ll find at least a few devices communicating over Modbus TCP/IP—PLCs, power meters, drives, analyzers, and sometimes entire SCADA systems built around it. Even though Modbus is one of the simplest industrial protocols, people still run into problems with connections, firewalls, and port settings. And most of those issues trace back to… Read More »

How to Monitor SCADA Protocol Traffic (Modbus RTU/TCP, IEC-104, DNP3, IEC-61850)

Monitoring SCADA protocol traffic is essential for diagnosing field issues, validating protocol behavior, troubleshooting mapping or timing problems, and improving the reliability of industrial automation systems. Whether the system uses legacy serial-based protocols such as Modbus RTU, IEC 60870-5-101, or DNP3 Serial, or modern TCP/IP-based protocols such as Modbus TCP, IEC 60870-5-104, DNP3 TCP, or IEC 61850, having… Read More »

IEC 104 News 2025: Latest Updates to IEC 60870-5-104 Standard, Security Extensions & Testing Tools

The IEC 60870-5-104 protocol remains one of the most widely implemented telecontrol standards in SCADA systems for electric power transmission and distribution. It extends IEC 60870-5-101 for operation over TCP/IP, enabling real-time data exchange between control centers and remote terminal units (RTUs). As of November 2025, the IEC 104 base standard itself has not changed, but significant progress… Read More »

IEC 60870-5-104 ASDU Structure Explained — Fields and Format

The Application Service Data Unit (ASDU) is the core of the IEC 60870-5-104 communication protocol. It defines how information is represented and exchanged between a controlling station (SCADA master) and controlled stations such as RTUs or IEDs. If the Application Protocol Data Unit (APDU) is the message envelope, the ASDU is the payload — carrying the actual telemetry… Read More »

DNP3 vs IEC 60870-5-104: Which Protocol Is Better for SCADA?

In modern SCADA (Supervisory Control and Data Acquisition) systems, choosing the right communication protocol can determine how efficiently, securely, and reliably data moves between control centers and field equipment. Two of the most widely used open standards are DNP3 (Distributed Network Protocol version 3) and IEC 60870-5-104. While both were designed for real-time monitoring and control, they differ… Read More »

DNP3 Secure Authentication Version 6 (SAv6): Encryption and Authorization Explained

Modern SCADA and utility automation systems face growing cybersecurity demands. The Distributed Network Protocol (DNP3)—the backbone of many control networks—has evolved to meet them. With the release of IEEE 1815-2020, the DNP3 Secure Authentication Version 6 (SAv6) specification brings authenticated encryption, centralized authorization, and simplified key management directly into the protocol. This article explains how SAv6 improves on… Read More »