| 100BASE-FX | A physical medium defined in the IEEE 802.3 Ethernet standard for local area networks (LANs) that uses fiber optic cabling | |
| 100BASE-TX | A physical medium defined in the IEEE 802.3 Ethernet standard for local area networks (LANs) that uses twisted-pair cabling category 5 or higher with RJ-45 connectors | |
| 620 series | Series of numerical protection and control relays for high-end protection and supervision applications of utility substations, and industrial switchgear and equipment | |
| AC | Alternating current | |
| ANSI | American National Standards Institute | |
| AR | Autoreclosing | |
| ASCII | American Standard Code for Information Interchange | |
| BI | Binary input | |
| BI/O | Binary input/output | |
| BO | Binary output | |
| CT | Current transformer | |
| DAN | Doubly attached node | |
| DC |
1. Direct current 2. Disconnector 3. Double command |
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| DNP3 | A distributed network protocol originally developed by Westronic. The DNP3 Users Group has the ownership of the protocol and assumes responsibility for its evolution. | |
| DPC | Double-point control | |
| EMC | Electromagnetic compatibility | |
| Ethernet | A standard for connecting a family of frame-based computer networking technologies into a LAN | |
| FIFO | First in, first out | |
| FTP | File transfer protocol | |
| FTPS | FTP Secure | |
| GOOSE | Generic Object-Oriented Substation Event | |
| HMI | Human-machine interface | |
| HSO | High-speed output | |
| HSR | High-availability seamless redundancy | |
| HTTPS | Hypertext Transfer Protocol Secure | |
| I/O | Input/output | |
| IEC | International Electrotechnical Commission | |
| IEC 60870-5-103 |
1. Communication standard for protective equipment 2. A serial master/slave protocol for point-to-point communication |
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| IEC 61850 | International standard for substation communication and modeling | |
| IEC 61850-8-1 | A communication protocol based on the IEC 61850 standard series | |
| IEC 61850-9-2 | A communication protocol based on the IEC 61850 standard series | |
| IEC 61850-9-2 LE | Lite Edition of IEC 61850-9-2 offering process bus interface | |
| IED | Intelligent electronic device | |
| IEEE 1686 | Standard for Substation Intelligent Electronic Devices' (IEDs') Cyber Security Capabilities | |
| IP address | A set of four numbers between 0 and 255, separated by periods. Each server connected to the Internet is assigned a unique IP address that specifies the location for the TCP/IP protocol. | |
| IRIG-B | Inter-Range Instrumentation Group's time code format B | |
| LAN | Local area network | |
| LC | Connector type for glass fiber cable, IEC 61754-20 | |
| LCD | Liquid crystal display | |
| LE | Light Edition | |
| LED | Light-emitting diode | |
| LHMI | Local human-machine interface | |
| MAC | Media access control | |
| MMS |
1. Manufacturing message specification 2. Metering management system |
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| Modbus | A serial communication protocol developed by the Modicon company in 1979. Originally used for communication in PLCs and RTU devices. | |
| Modbus TCP/IP | Modbus RTU protocol which uses TCP/IP and Ethernet to carry data between devices | |
| NC | Normally closed | |
| NO | Normally open | |
| NPS | Negative phase sequence | |
| PCM600 | Protection and Control IED Manager | |
| PO | Power output | |
| PRP | Parallel redundancy protocol | |
| PTP | Precision Time Protocol | |
| REM620 | Motor protection and control relay | |
| RIO600 | Remote I/O unit | |
| RJ-45 | Galvanic connector type | |
| RSTP | Rapid spanning tree protocol | |
| RTD | Resistance temperature detector | |
| RTU | Remote terminal unit | |
| SAN | Single attached node | |
| Single-line diagram | Simplified notation for representing a three-phase power system. Instead of representing each of three phases with a separate line or terminal, only one conductor is represented. | |
| SMV | Sampled measured values | |
| SNTP | Simple Network Time Protocol | |
| SO | Signal output | |
| TCS | Trip-circuit supervision | |
| VT | Voltage transformer | |
| WAN | Wide area network | |
| WHMI | Web human-machine interface |