top IoT communication protocols for connected ecosystems in smart buildings

top IoT communication protocols for connected ecosystems in smart buildings

top IoT communication protocols
for connected ecosystems in
smart buildings

Building Automation Systems (BAS) are vast interconnected networks of devices performing various functions, all linked for a single purpose — to help buildings operate efficiently. And this interoperability is only possible when all devices ‘communicate’ seamlessly with each other, which involves data being ‘read’ from various critical systems like heating, ventilation, and air conditioning (HVAC), lighting, and more. This interaction is governed by a set of digital rules or ‘communication protocols’, which can be either proprietary or open source, and have been ubiquitous in the BAS world since smart buildings were first incepted.

the early years of the Building Automation industry

Traditionally an oligopoly, the building automation industry was plagued by proprietary systems and protocols delivered by a handful of manufacturers operating in the market. These closed systems only allowed upgrades and expansions with the same brand’s equipment, creating vendor lock-in that limited flexibility for building owners. Buildings became highly fragmented with multiple closed systems operating in silos. Device management became complicated, budgets swelled, and competitive options from alternate vendors remained in wish lists.

the rise of communication protocols

Pioneered by two open communication protocols in the 1980s — BACnet and LonWorks — automation in buildings went mainstream by the 2000s as more customers began demanding non-proprietary standards. IoT and cloud technologies further amplified this demand, and automation within smart buildings eventually started to converge into one cohesive network linked by open communication protocols.


Today, BAS employs multiple open data communication standards, and this article highlights the top four popular protocols – BACnet, Modbus, DALI, and KNX.


One of the most prominent open communication protocols worldwide — it has almost an 80% share of the market in North America and dominates around 60% of the European market — BACnet was developed in 1987 as a counter to the proprietary systems created by then-leading building equipment manufacturers. It became an ANSI standard in 1995 and an ISO standard in 2003. Originally designed for HVAC equipment, BACnet is today widely used for lighting control, access control, elevator controls, security applications, energy meters, and more. The protocol has enabled interoperability among smart building devices, connecting every system securely while offering owners flexibility to customise their solutions as per specific use cases.


Standard Type: ASHRAE | ANSI | ISO

Softdel is home to the world’s first BACnet Test Reference Lab certifying more than 90% of BACnet-compliant devices for the building automation industry.

Using BACnet, a leading manufacturer of connectivity products could seamlessly integrate a smart lighting solution with their building management system (BMS). BACnet integrated with PoE enabled the customer to control everything from LED light status, to real-time energy consumption, to ambient temperature, to zone humidity, and even air-quality monitoring. Advanced features like the grouping of fixtures and daylight calibration were also made possible due to BACnet. Additionally, this BACnet compliance opened up the possibility of interoperability of the customer's platform with various building management systems, which otherwise would have required major architectural changes. All this without increasing the overall cost of operations!

Read the complete case study here

BACnet played a key role in achieving sustainability goals for a leading manufacturer of engineered water solutions, by building a gateway solution that leveraged this communication protocol for enabling smart water management in buildings. BACnet, together with LoRA technology, created a solution that seamlessly integrated with various BMS, thus drastically reducing field visits, increasing operational efficiency, and gaining the customer a major market share in water management solutions.

Read the complete case study here


Developed in 1979 to allow communication between programmable logic controllers (PLCs), Modbus transmits information over serial lines between electronic devices. The protocol was originally developed by Modicon (now part of Schneider Electric) and is currently managed by the Modbus Organization, an association of Modbus-compliant users and device suppliers. Different versions of this standard exist for Ethernet, Serial, and IP communications.


Modbus holds a steady market share in both American and European markets, mainly for industrial applications. Predominantly used by industrial electronic devices because of its interoperability with PLCs, Modbus is increasingly finding its footing in the digital buildings industry as well.

Softdel’s revolutionary EdificeEdge Building IoT Gateway easily integrates with both BACnet and Modbus, creating an IoT-ready framework with open standardisation at the edge?

In a solution built for a leading HVAC manufacturer, the EdificeEdge IoT gateway communicated over protocols like Modbus and BACnet to manage and control data coming from their extensive range of HVAC units. The engineered solution further collected real-time data over the communication protocols, for tasks like predictive and preventive maintenance, thus bringing in energy efficiency, and much more.

For a major manufacturer of boilers and chillers, EdificeEdge not only collected data over Modbus and other communication protocols but also linked the customer's chillers with sensors' and sub-sensor data, allowing the customer to create and use actionable insights for better energy management, reduced device downtimes, and lower operating costs.

For a technology company engaged in building management and energy solutions, a connector built using our EdificeEdge platform leveraged Modbus plus other communication protocols to provide comprehensive data on building management systems, giving our customer a greater degree of control over building operations.


One of the most common protocols dedicated to digital lighting control is Digital Addressable Lighting Interface or DALI which has been around since the 1990s. Introduced by the IEC (International Electrotechnical Commission) and DiiA (Digital Illumination Interface Alliance), DALI is a two-way protocol that enables communication and control of all components in a lighting system. DALI is now widely recognised as the global standard for lighting control, and there exists a wide range of lighting control components, specifically LED drivers, that support a direct DALI connection. A later version of the DALI protocol, DALI-2, further increases interoperability between devices and supports input devices, application controllers, and other control devices.

top IoT communication protocols for connected ecosystems in smart buildings

DALI is the only protocol that exclusively controls lighting, making DALI somewhat of an enhanced lighting control engine, compatible and interoperable with pretty much any smart lighting device globally.

Softdel partnered with one of the leaders in smart lighting solutions to create a DALI-backed platform that interlinked a comprehensive set of wired and wireless smart lighting products with one server. Integrating DALI helped the platform interoperate with this wide breadth of devices easily, and incorporate all essential lighting control functions like dimming, temperature and colour control, and binary control, with relative ease. This solution is now in use in one of America’s largest airports.

Read the complete case study here


The KNX protocol, or Konnex bus, is a communication standard used for home and building control. Owned by the KNX Association, the protocol can govern HVAC functions, lighting, blinds and shutters, security systems, energy usage, and more. KNX is easily installed in both commercial and residential built environments, and the fact that it removes the need for a centralised intelligence system is a huge draw for the industry and explains why more than 370 million KNX devices have been installed in homes and buildings worldwide.


KNX is especially popular in Europe and is considered to be the second most widely used protocol in that region. KNX is fast gaining popularity in countries like China and North America as well, although sometimes enthusiasm is a bit muted due to loyalty towards older communication protocols.

top IoT communication protocols for connected ecosystems in smart buildings

KNX actually evolved from three previous standards — the European Home Systems Protocol (EHS), BatiBUS, and the European Installation Bus (EIB or Instabus).

Today’s building owners and manufacturers of smart devices are increasingly mandating the use of open protocols like BACnet, Modbus, DALI, and KNX for building and industrial equipment. With the Internet of Things (IoT) transforming the way we operate and build devices, and the compelling convenience of open protocols, such protocols are now the norm or even the mandate in every building.

Explore the industry-standard BACnet, Modbus, KNX, and DALI communication protocols with Softdel. No more communication problems between smart building systems!

top IoT communication protocols for connected ecosystems in smart buildings

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