This is a list of communication protocols used for the automation of processes (industrial or otherwise), such as for building automation, power-system automation, automatic meter reading, and vehicular automation.

Process automation protocols

• AS-i – Actuator-sensor interface, a low level 2-wire bus establishing power and communications to basic digital and analog devices
• BSAP – Bristol Standard Asynchronous Protocol, developed by Bristol Babcock Inc.
• CC-Link Industrial Networks – Supported by the CLPA
• CIP (Common Industrial Protocol) – can be treated as application layer common to DeviceNet, CompoNet, ControlNet and EtherNet/IP
• ControlNet – an implementation of CIP, originally by Allen-Bradley
• DeviceNet – an implementation of CIP, originally by Allen-Bradley
• DF-1 - used by Allen-Bradley ControlLogix, CompactLogix, PLC-5, SLC-500, and MicroLogix class devices
• DNP3 - a protocol used to communicate by industrial control and utility SCADA systems
• DirectNet – Koyo / Automation Direct proprietary, yet documented PLC interface
• EtherCAT
• Ethernet Global Data (EGD) – GE Fanuc PLCs (see also SRTP)
• EtherNet/IP – IP stands for "Industrial Protocol". An implementation of CIP, originally created by Rockwell Automation
• Ethernet Powerlink – an open protocol managed by the Ethernet POWERLINK Standardization Group (EPSG).
• FINS, Omron's protocol for communication over several networks, including Ethernet.
• FOUNDATION fieldbus – H1 & HSE
• HART Protocol
• HostLink Protocol, Omron's protocol for communication over serial links.
• Interbus, Phoenix Contact's protocol for communication over serial links, now part of PROFINET IO
• MECHATROLINK – open protocol originally developed by Yaskawa, supported by the MMA
• MelsecNet, and MelsecNet II, /B, and /H, supported by Mitsubishi Electric.
• Modbus PEMEX
• Modbus Plus
• Modbus RTU or ASCII or TCP
• MPI – Multi Point Interface
• OSGP – The Open Smart Grid Protocol, a widely use protocol for smart grid devices built on ISO/IEC 14908.1
• OpenADR – Open Automated Demand Response; protocol to manage electricity consuming/controlling devices
• Optomux – Serial (RS-422/485) network protocol originally developed by Opto 22 in 1982. The protocol was openly documented^[1] and over time used for industrial automation applications.
• PieP – An Open Fieldbus Protocol
• Profibus – by PROFIBUS & PROFINET International (PI)
• PROFINET - by PROFIBUS & PROFINET International (PI)
• RAPIEnet – Real-time Automation Protocols for Industrial Ethernet
• Honeywell SDS – Smart Distributed System – Originally developed by Honeywell. Currently supported by Holjeron.
• SERCOS III, Ethernet-based version of SERCOS real-time interface standard
• SERCOS interface, Open Protocol for hard real-time control of motion and I/O
• GE SRTP – GE Fanuc PLCs
• Sinec H1 – Siemens
• Sinec L1 – Siemens
• Sinec L2 DP/FMS – Siemens
• SynqNet – Danaher
• TTEthernet – TTTech

Industrial control system protocols

• Data Distribution Service from the Object Management Group
• MTConnect
• OPC Unified Architecture
• Open Platform Communications, formerly OLE for process control

Building automation protocols

• 1-Wire – from Dallas/Maxim
• BACnet – for Building Automation and Control networks, maintained by ASHRAE Committee SSPC 135.
• BatiBUS - merged to KNX
• C-Bus Clipsal Integrated Systems Main Proprietary Protocol
• CC-Link Industrial Networks, supported by Mitsubishi Electric
• DALI - Digital Addressable Lighting Interface specified in IEC 62386.
• DSI - Digital Serial Interface for the controlling of lighting in building, precursor to DALI.
• Dynet - lighting and automation control protocol developed in Sydney, Australia by the company Dynalite
• EnOcean – Low Power Wireless protocol for energy harvesting and very lower power devices.
• European Home Systems Protocol (EHS) - merged to KNX
• European Installation Bus (EIB) named also Instabus - merged to KNX
• INSTEON - SmartHome Labs Pro New 2-way Protocol based on Power-BUS.
• KNX – Standard for building control. Previously Batibus/EHS/EIB
• LonTalk – protocol for LonWorks technology by Echelon Corporation
• Modbus RTU or ASCII or TCP
• oBIX - Open Building Information Exchange is a standard for RESTful Web Services-based interfaces to building control systems developed by OASIS.
• UPB - 2-way Peer to Peer Protocol
• VSCP - Very Simple Control Protocol is a free protocol with main focus on building- or home-automation
• xAP – Open protocol
• X10 – Open standard for communication among electronic devices used for home automation (domotics)
• Z-Wave - Wireless RF Protocol
• Zigbee – Open protocol for Mesh Networks

Power system automation protocols

• DNP3 – Distributed Network Protocol
• IEC 60870-5
• IEC 61850
• IEC 62351 – Security for IEC 60870, 61850, DNP3 & ICCP protocols

Automatic meter reading protocols

• ANSI C12.18
• DLMS/IEC 62056
• IEC 61107
• M-Bus
• OMS
• Zigbee Smart Energy 2.0
• Modbus
• ANSI C12.21
• ANSI C12.22

Automobile / Vehicle protocol buses

• Controller Area Network (CAN) – an inexpensive low-speed serial bus for interconnecting automotive components
• FlexRay – a general purpose high-speed protocol with safety-critical features
• IDB-1394
• IEBus
• J1708 – RS-485 based SAE specification used in commercial vehicles, agriculture, and heavy equipment.
• J1939 and ISO11783 – an adaptation of CAN for agricultural and commercial vehicles
• Keyword Protocol 2000 (KWP2000) – a protocol for automotive diagnostic devices (runs either on a serial line or over CAN)
• Local Interconnect Network (LIN) – a very low cost in-vehicle sub-network
• Media Oriented Systems Transport (MOST) – a high-speed multimedia interface
• Vehicle Area Network (VAN)
• UAVCAN - a lightweight protocol for in-vehicle communication over CAN or Ethernet