Nessum Basics FAQ: What It Does and Why It’s Unique

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If you’ve never heard of Nessum, you’re not alone.
Even though the technology behind it has been around since the early 2000s under the name HD-PLC, it’s still relatively unknown outside of specific industries.
So, the first reaction many people have is:
“Nessum? What’s that supposed to be?”

Here’s the simple answer:
   Nessum is like a networking bridge that lets your devices talk to each other — whether they use Ethernet or old-fashioned serial connections — all over the wires you already have.

Instead of pulling new cables or replacing old equipment, Nessum makes it possible to:

  • Plug in Ethernet devices and connect them instantly
  • Keep using legacy serial devices like sensors or controllers
  • Extend networks across power lines, twisted pairs, or almost any existing wiring

And while the roots of Nessum come from HD-PLC, it has continued to evolve with industrial use in mind — adding flexibility, reliability, and scalability that make it practical for today’s building and factory networks.

In this FAQ, we’ll cover the most common questions to give you a clear picture of what Nessum does and why it matters.

 

Q1. How is a Nessum network structured?

A Nessum network consists of one Master device and multiple Terminal devices.

Think of the Master as the main point that organizes the network, but devices can also communicate directly with each other. This simple structure allows all connected devices to exchange information reliably over the same wiring, whether it’s twisted pair or other types of existing cables.

Q2. What is the basic function of Nessum?

Nessum works like a plug-and-play bridge.

  • For Ethernet devices: just plug them in, and packets flow as if through a standard Layer 2 (L2) switch.

  • For serial devices: data is encapsulated into Ethernet packets and sent across the network.

Nessum supports Modbus RTU and Modbus ASCII by default, and can also bridge other serial protocols if destination address information is defined.

This dual bridging allows Nessum to connect both modern Ethernet devices and legacy serial equipment seamlessly.

Q3. Is Nessum just another L2 switch?

Not exactly.
While Nessum behaves like an L2 switch from the outside, it isn’t competing with network switches. The big difference is the medium:

  • Nessum can operate over existing power lines, twisted pairs, or almost any wire, and even short-range wireless.

At the same time, Nessum provides many of the same functions as an L2 switch, including:

  • VLAN support for flexible network segmentation
  • MAC address filtering for traffic control and security
  • PTPv2 support for precise time synchronization across devices

This makes it much more than just a simple bridge.

Q4. Is the communication secure?

Yes.
The Master device handles authentication and encryption key distribution. Communication uses AES-128 encryption, with keys dynamically updated to maintain strong security.
This ensures reliability even in industrial or building environments.

Q5. Can multiple Nessum networks be connected together?

Yes.

  • You can directly link multiple Nessum networks using Ethernet cables or through another L2 switch.
  • From the outside, the whole system still behaves just like a standard L2 switch.

This makes expansion straightforward.

Q6. What is Multi-hop, and why does it matter?

Multi-hop allows packets to automatically route across multiple Nessum devices within the same network.

  • Each hop extends the effective communication range.
  • From the outside, it still looks like a simple L2 switch — no extra setup required.

This feature is particularly important for replacing long-distance serial communication. With Multi-hop, Nessum can cover distances far beyond a single Ethernet or serial link, making legacy serial networks realistic to upgrade.

Conclusion

Nessum is not just another switch. It is a unifying bridge that:

  • Extends IP networking over existing wiring
  • Connects both Ethernet and serial devices (with Modbus RTU/ASCII support)
  • Provides key L2 switch features like VLAN, MAC filtering, and PTPv2
  • Ensures secure communication with AES-128 encryption
  • Scales across long distances with Multi-hop

By combining these capabilities, Nessum makes the transition from legacy systems to modern IP networks both practical and cost-effective.

 

Get Started Today

Order your Evaluation Kit and experience the benefits of Nessum today!

 

About the Author
Kengo Tamukai is a senior engineer specializing in wired and wireless communication technologies. With over 20 years of experience in LSI design, system architecture, and technical marketing, his expertise spans SoC design, OFDM-based technologies, and hybrid communication systems, driving innovation in modern digital networks.

Long-Range Microsecond Time Synchronization with PTPv2 over Nessum Networks

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To achieve microsecond-level time synchronization, PTPv2 (Precision Time Protocol version 2) is one of the most effective approaches. By using Layer 2 (L2) switches that support PTPv2 over CAT5 cables, it is possible to distribute highly accurate time. However, this method is limited by its reliance on a star topology, which tends to increase cable lengths and network complexity.

Moreover, when synchronization is required over distances of several kilometers, optical fiber becomes necessary, significantly increasing infrastructure costs. This makes the approach unsuitable for many IoT applications, where cost, simplicity, and flexibility are critical.

The combination of Nessum and PTPv2 overcomes these challenges.

Nessum with PTPv2: A Flexible and Scalable Solution

Nessum supports PTPv2 as defined in IEEE 1901c. In a Nessum network, the system functions as a boundary clock, with time distributed from a Nessum Master to all connected Terminals.

Unlike traditional PTPv2 deployments, Nessum allows for free topology—such as bus, tree, or ring structures—over a variety of wired media including twisted-pair and power lines. This greatly reduces the need for centralized cabling and optical fiber, lowering costs while enabling long-range synchronization across several kilometers.

This architecture enables accurate time distribution while also providing devices with Nessum’s inherent features: robust signal transmission, high security, and flexible channel functionality.

Additionally, PTPv2’s delay measurement mechanism enables precise estimation of path delays, which can also be used for physical length measurements between devices.

Potential Applications

Monitoring of Large-Scale Infrastructure

For critical infrastructure such as bridges and dams, Nessum enables microsecond-accurate data synchronization across widely dispersed sensors—such as deflection sensors on bridge girders or water level gauges in dam reservoirs. This precision supports early detection of subtle structural deformations or signs of deterioration, contributing to predictive maintenance strategies and more reliable structural health assessments, especially during large-scale natural disasters.

Enhancing Ultrasonic Indoor Positioning

Ultrasonic indoor positioning systems can achieve centimeter-level accuracy, but they rely heavily on microsecond-level synchronization between multiple sensors. Nessum simplifies this requirement by providing microsecond-accurate time synchronization over 1–2 km of copper wiring. This eliminates the need for traditional fiber optics or complex PTP wiring, making it easier to build large-scale ultrasonic sensor networks. The result is a flexible and cost-effective solution for high-precision applications such as AGV navigation in factories, control of precision robotics in delicate operations, and real-time location tracking in medical facilities.

Enhanced Security through Acoustic Monitoring

In factories, large-scale facilities, and public spaces, deploying widely distributed acoustic sensors—such as microphone arrays—synchronized with microsecond-level precision enables highly accurate localization of abnormal sounds, including gunshots, screams, or breaking glass. This enables real-time, wide-area surveillance that conventional systems struggle to achieve, supporting swift initial responses and effective evidence preservation during incidents or emergencies, thereby significantly enhancing overall security.

Timestamped Event Monitoring in Smart Grids

In smart grid systems, which increasingly integrate distributed energy resources like solar and wind power, accurately timestamping events from smart meters, circuit breakers, and power quality sensors down to the microsecond level is essential. Such synchronization ensures grid stability, facilitates rapid fault analysis, and improves the efficiency of energy exchange. Given the wide geographic distribution of power infrastructure, Nessum’s ability to provide long-range, high-precision synchronization over copper wiring is particularly valuable.

High-Precision Time Synchronization for Building and Facility Emergency Response

In buildings and large facilities, emergency systems such as ventilation fans, lighting, emergency doors, and fire alarms must operate in a coordinated manner during incidents like fires. Microsecond-level time synchronization ensures these systems activate without delay and at optimal timing, enabling accurate monitoring of smoke propagation and the establishment of safe and rapid evacuation routes. This level of coordination is essential for protecting both lives and assets, with its importance increasing proportionally to facility size.

Synchronization of Train and Railway Signaling Infrastructure

In railway infrastructure, where safety and timing are paramount, microsecond-level time synchronization is critical for operations such as signal control, level crossing management, and train position detection. Nessum provides a compelling solution for these applications, particularly in areas where installing optical fiber is physically or economically challenging. By leveraging existing copper wiring, operators can enhance both safety and operational efficiency without large-scale infrastructure overhauls.

Immersive Experience Synchronization in Entertainment Venues

In large-scale entertainment venues—such as outdoor arenas, multi-zone facilities spanning over a kilometer, and expansive theme parks—microsecond-level synchronization of audio systems, large video displays, lighting, and special effects eliminates perceptible delays between sound and visuals. This enables seamless coordination of all sensory elements, delivering a continuous and highly immersive storytelling experience that enhances audience engagement and elevates overall visitor satisfaction.

 

Unlocking New Possibilities

The combination of PTPv2 and Nessum removes the traditional limitations of time-synchronized applications.

By enabling microsecond-level synchronization over long distances and various wiring infrastructures—including twisted-pair, coaxial cables, and even power lines—this solution addresses the cost, complexity, and topology constraints that have hindered traditional deployments. It opens the door to a wide array of time-sensitive applications in sectors ranging from infrastructure monitoring and industrial automation to transportation, energy, and entertainment.

With its flexibility, scalability, and robustness, Nessum with PTPv2 is poised to become a core enabler of next-generation synchronized systems, allowing engineers and developers to reimagine what’s possible in connected environments.

 

Get Started Today

Order your Evaluation Kit and experience the benefits of Nessum today!

 

About the Author
Kengo Tamukai is a senior engineer specializing in wired and wireless communication technologies. With over 20 years of experience in LSI design, system architecture, and technical marketing, his expertise spans SoC design, OFDM-based technologies, and hybrid communication systems, driving innovation in modern digital networks.

Before You Try Power Line Communication (PLC): 5 Key Challenges That Could Kill Your Connection

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Power Line Communication (PLC) sounds like a dream: transforming your existing electrical wiring into a data network, saving you the cost and mess of new cables. It’s a brilliant concept with huge potential.

But in real-world situations, PLC doesn’t always work smoothly. There are several issues that can block or weaken the signal. If you don’t pay attention to these, your connection might be slow, unstable, or fail completely.

Here are five important challenges to watch out for when using PLC.

 

1. Signal Fade-Out Over Long Cable Runs

Even though power cables carry electricity well, they’re not perfect for carrying high-speed data signals. Over long distances—especially at the high frequencies used by PLC—the signal gradually fades. It’s like a voice getting quieter the farther it travels.

This signal fading depends on the cable material, the length of the cable and the frequency being used. As a rough guide:

  • Over 100 meters, the signal may drop to about one-tenth (1/10) of its original strength.
  • Over 400 meters, the signal may drop to about one-thousandth (1/1,000).

This kind of loss usually isn’t noticeable in homes, but it becomes important in large buildings like factories or offices with long wiring.

 

What you can do:

  • Home use: Most homes don’t have cable runs longer than 100 meters, so the signal stays strong enough for PLC to work well.
  • Industrial use: In large facilities with long wiring, using lower-frequency PLC is recommended. Some PLC systems like Nessum support long-distance communication by adjusting the frequency.

2. Too Many Paths for the Signal (Branch Splitting)

Your power wiring usually splits into many branches—especially at the breaker box. This is where the signal can get lost or bounced around.

At low frequencies (like normal electricity), this isn’t a big deal. But at the high frequencies used by PLC, each branch splits the signal more and more—like shining a flashlight through lots of mirrors. The more branches there are, the more the signal gets scattered and weakened.

In the worst case, each branch can reduce the signal by half, and if there are multiple branches in a row, the loss becomes exponential: With 20 branches, depending on the spacing between them, the loss can range from 1/20 to 1/1,000,000.

Note: This simplified estimate does not account for additional signal reflections from impedance mismatches.

What you can do:

  • Home use: Most homes have up to 10 branches, and because the branches are spaced closely together, the signal loss is usually minimal and not a problem for modern PLC devices.
  • Industrial use: In buildings with many and widely spaced branches, it’s a good idea to install signal repeaters (devices that boost the signal) in each breaker box.

3. Devices That Absorb Your Signal (Low Impedance Loads)

Most appliances and electronic devices (like TVs, washing machines, or PCs) are designed to reduce noise, which is good for safety—but not so good for PLC. These devices often include special parts (called X-capacitors) that “absorb” high-frequency signals like those used by PLC. As a result, communication signals are weakened to about 1/100 to 1/1,000.

 

Also, because these signals travel at high frequencies, even a short distance (like 30–50 cm) between the device and the outlet can change how much the signal is affected.

What you can do:

  • Home use: Try using a short power extension cord (1 meter or so) between the outlet and your noisy device. It often improves the signal.
  • Industrial use: Avoid plugging unknown or unfiltered machines into the same power line as your PLC device. You can also install special parts (like coils) to help keep the signal strong.

4. Noise from Electrical Equipment

Some devices, especially those with motors (like hair dryers or factory machines), create a lot of electrical “noise” that spreads into the power lines. This noise can interfere with the PLC signal, like trying to talk in a room full of shouting people.

Even advanced PLC systems can struggle with noise.

For example, Nessum is capable of maintaining communication even when the signal strength is reduced to less than one ten-billionth (1/10,000,000,000) of its original level. However, when strong noise is present, this high sensitivity can’t be fully utilized, and communication may still fail.

What you can do:

  • Home use: Use noise filters (small plug-in devices) to reduce interference.
  • Industrial use: Install EMC filters to separate noisy machines from your communication lines.

5. Transformers – The Signal Can’t Cross Them

Large buildings often use transformers to change high-voltage electricity into a lower voltage for regular use. Unfortunately, PLC signals can’t pass through transformers easily. It’s like trying to speak through a thick wall—most of the sound gets blocked.

 

What you can do:

  • Home use: This usually isn’t a problem—homes rarely have transformers inside.
  • Industrial use: Use wireless bridges (like Wi-Fi or specific PLC wireless products such as Nessum-Air) to send signals across different parts of the building.

Conclusion

PLC is a great way to turn your power outlets into network ports without installing new cables. But it’s not plug-and-play in every situation. Real-world environments—especially in industrial or complex buildings—introduce challenges like signal loss, noise, and electrical interference.

The good news:
If you understand and plan for these 5 key challenges, you can enjoy fast and stable PLC communication both at home and in large facilities.

 

About the Author
Kengo Tamukai is a senior engineer specializing in wired and wireless communication technologies. With over 20 years of experience in LSI design, system architecture, and technical marketing, his expertise spans SoC design, OFDM-based technologies, and hybrid communication systems, driving innovation in modern digital networks.

The Future of Building Networks: Broadband PLC as the Communication Backbone

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As decarbonization efforts accelerate, Zero Emission Buildings (ZEBs) have become a key target in climate policy. Achieving ZEB status requires automation systems that can efficiently monitor and control major energy loads like HVAC and lighting.

While large buildings can absorb the cost of complex infrastructure, small-to-medium-sized buildings often struggle with the high expense of separate power and communication networks. A more integrated, cost-effective solution is needed.

Broadband Power Line Communication (PLC) offers a promising alternative. By using existing power lines for both data and energy transmission, PLC reduces wiring complexity and cost. When paired with wireless technologies, it supports a hybrid architecture that enables flexible, scalable control across a building.

With these capabilities, broadband PLC is emerging as a next-generation communication backbone for building automation.

 

Current Building Automation Architecture

Most building automation systems today rely on RS-485 communication. Although mature and widely used, RS-485 presents several limitations:

  • It requires separate wiring for communication and power, increasing material and labor costs.
  • Often, the communication and power networks have mismatched topologies, complicating installation and maintenance.
  • Its daisy-chain topology is fragile—failure of a single device can impact the entire network.
  • It is susceptible to common installation errors, such as flipped polarity, grounding issues, and missing end-of-line (EOL) resistors.

To meet safety regulations, RS-485 systems typically use low-voltage power lines (e.g., AC24V, DC24V, DC30V), which do not require licensed electricians for installation.

Alternatives to RS-485

Several alternatives to RS-485 are currently being explored:

– Wireless

Wireless systems eliminate the need for communication wiring and enable flexible device placement. However, they pose challenges in terms of reliability and interference:

  • Signal quality is highly sensitive to changes in the physical layout—partition walls, for example, can cause over 10 dB of attenuation.
  • Extending coverage often requires reducing bandwidth or increasing transmission power, both of which can cause interference with nearby systems.
  • Reliable operation demands advanced RF planning and detailed site surveys.

 

– 10Base-T1L with PoDL

10Base-T1L enables simultaneous transmission of data and power over a single twisted pair using Power over Data Line (PoDL) technology, supporting up to 60W of power. While this simplifies wiring, it has notable constraints:

  • It supports only point-to-point communication, requiring either:
    • A star topology with L2 switches, or
    • A daisy-chain topology with dual-port devices.
  • When PoDL is used, the number of daisy-chained nodes is limited by power distribution constraints.

Despite its high bandwidth and low latency, its rigid topological requirements can limit flexibility in real-world building layouts.

Broadband Power Line Communication (PLC)

Broadband PLC leverages existing power lines for data transmission, making it a compelling solution for building automation—especially over dedicated power lines like AC24V or DC24V. Its key advantages include:

  • Reduced wiring cost by eliminating separate communication lines.
  • Predictable network behavior—since only automation devices are connected, interference is limited and controllable.
  • Support for bus and free topology, aligning naturally with the structure of power line networks.

In addition to these benefits, broadband PLC also addresses several known limitations of RS-485.

RS-485 Limitation  Broadband PLC Advantage
Daisy-chain topology only Supports Free topology (bus, star, daisy, loop)
Flipped polarity Polarity-agnostic modulation schemes
Grounding problems Isolation via compact, low-cost transformers
EOL resistance requirement No EOL resistor required

 

 

– Technical Considerations

Even with dedicated lines, PLC must address certain technical issues:

  • X-capacitors in power supplies lower line impedance, attenuating communication signals.
  • Noise from switching devices can degrade signal quality.

To mitigate these issues:

  • Inductive impedance elements (e.g., coils) can be added to stabilize line impedance and suppress noise.
  • Multi-hop PLC protocols, such as Nessum, help maintain stable communication even over high attenuation or in noisy environments.

These features enable deterministic network behavior, simplifying system design. Nessum’s multi-hop capability supports up to 1,024 nodes, allowing the network to scale effectively—making it highly suitable for building automation applications.

 

 Extended Applications

By adopting the same architecture, even higher-voltage AC lines (e.g., AC110V or AC230V) can serve as reliable communication channels. This enables the use of PLC for power-hungry applications while maintaining the same benefits, making this approach a viable communication backbone for building automation—even in high-demand environments such as HVAC systems.
In this scenario, adding EMC filters at the origin of the power line further enhances signal stability.

 

Furthermore, by combining broadband PLC with wireless technology, a hybrid architecture can be realized: PLC serves as the backbone network, while wireless provides flexible access to end devices such as lighting fixtures and sensors. This approach enables centralized control over the two major sources of energy consumption in buildings—HVAC and lighting—through a cost-effective and scalable infrastructure.

 

 

Conclusion

Broadband Power Line Communication presents a practical, scalable, and cost-effective alternative to traditional wiring in building automation. By leveraging existing power lines and modern PLC technologies, it enables:

  • Simplified installation
  • Reduced material and labor costs
  • Resolution of legacy system issues such as RS-485
  • Deployment of robust, flexible networks—even in retrofit scenarios

Moreover, when combined with wireless technologies in a hybrid architecture, broadband PLC can act as a reliable communication backbone, enabling centralized control of both HVAC and lighting—the two primary sources of energy consumption in buildings. This integrated approach supports the development of smart, energy-efficient infrastructures and offers a viable path toward Zero Emission Buildings (ZEB), especially for small-to-medium-sized facilities seeking both sustainability and affordability.

 

Get Started Today

Order your Evaluation Kit and experience the benefits of Nessum today!

 

About the Author
Kengo Tamukai is a senior engineer specializing in wired and wireless communication technologies. With over 20 years of experience in LSI design, system architecture, and technical marketing, his expertise spans SoC design, OFDM-based technologies, and hybrid communication systems, driving innovation in modern digital networks.

Expanding Robust Communication to Twisted-Pair & Any Wire Networks

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Originally designed for reliable data transmission over noisy power lines, Nessum (formerly HD-PLC) is now evolving to support a broader range of communication infrastructures, including twisted-pair networks.

Challenges in Power Line Communication

Communicating over power lines presents several major challenges:

  • Noise Interference – Electrical devices generate various types of noise that can disrupt communication.
  • Signal Reflection – The flexibility of power line connections causes complex signal reflections, leading to frequency-selective fading.
  • High Attenuation – Power circuits have very low impedance, often just a few ohms, resulting in over 10 dB of signal loss.

Without advanced modulation and error correction, reliable communication under these conditions would be nearly impossible.

Nessum’s Advanced Solutions

To address these challenges, Nessum integrates state-of-the-art technologies that ensure exceptional robustness in harsh environments.

The following figure shows the block diagram of the Nessum SoC.

  • Transmission (TX): The sending packet is queued in the Nessum MAC, which manages retries, data concatenation, QoS, and other functionalities. The packet is then transferred to the Nessum PHY, where it undergoes LDPC-CC encoding, data mapping, and modulation via inverse OFDM. The modulated digital data is converted to analog by the ADC in the AFE and transmitted to the network.
  • Reception (RX): The received signal is amplified and converted to digital data by the DAC in the AFE. The digital data is then demodulated via an OFDM demodulator, equalized, and error-corrected by FEC. Based on the error correction result, the Nessum MAC sends either an ACK or NACK and reconstructs the packet.

 

– LDPC-CC Forward Error Correction (FEC) and Retry Mechanism

This powerful FEC method effectively corrects errors caused by noise. Additionally, a MAC-layer retry mechanism enhances data recovery when FEC alone is insufficient. Together, these features ensure robust communication, even in environments with severe electromagnetic interference (EMI), such as electric fast transients (EFT) and surges.

The following figure illustrates this mechanism. If only a small number of data bits are corrupted, FEC can correct the errors, and an ACK is sent. However, if many data bits are corrupted, FEC cannot correct them, prompting a NACK to request a retry.

 

– OFDM for Reflection Management

Orthogonal Frequency-Division Multiplexing (OFDM) effectively mitigates the impact of frequency-selective fading by dynamically allocating data to high CINR (Carrier-to-Interference-plus-Noise Ratio) carriers. This allocation is continuously updated as network conditions change, ensuring optimal performance and enabling flexible, free-topology network configurations.

The following figure provides an example.

When using 32PAM, each carrier can load 5 bits of data.

However, if reflections occur, not all carriers can maintain a good CINR, leading to potential errors when loading the maximum data bits.


To minimize errors, more bits are allocated to carriers with good CINR, while fewer bits are assigned to carriers with poor CINR.

 

– State-of-the-Art Analog Front-End

With a high dynamic range exceeding 100 dB, Nessum’s advanced analog front-end technology effectively mitigates severe signal attenuation caused by low impedance. This high dynamic range enables point-to-point communication over distances of more than 1 km. It also ensures stable communication over several hundred meters, even in the presence of cable and splitter losses.

The following figure illustrates this concept. When a 1 km cable is used between Nessum devices, the typical cable loss at a 10 MHz bandwidth is approximately 0.5–1.5 dB/m. If a cable with a loss of 0.1 dB/m is used, the total cable loss amounts to approximately 100 dB (0.1 dB/m × 1,000 m). In this scenario, a dynamic range exceeding 100 dB enables successful signal decoding.

 

Beyond Power Lines: A New Era of Connectivity

By applying these innovations to twisted-pair and other wire-based networks, Nessum extends its robust, interference-resistant communication technology beyond traditional power line systems. As industries seek greater flexibility and reliability, Nessum is paving the way for the next generation of high-performance networking solutions.

 

Get Started Today

Order your Evaluation Kit and experience the benefits of Nessum today!

 

About the Author
Kengo Tamukai is a senior engineer specializing in wired and wireless communication technologies. With over 20 years of experience in LSI design, system architecture, and technical marketing, his expertise spans SoC design, OFDM-based technologies, and hybrid communication systems, driving innovation in modern digital networks.