What Comes After the Discontinued Neuron Chip ?
Renesas Electronics has announced the discontinuation of the Neuron® chip.
For many building automation and industrial control systems, this raises a critical question:
How can existing LonWorks FT-10 networks (ISO/IEC 14908-3) be maintained or modernized without rewiring entire buildings?
The answer depends on whether the priority is compatibility or evolution.
Why LonWorks FT-10 Was So Valuable
FT-10 became widely adopted in systems certified by LonMark International because it supported free topology wiring.
Free topology means:
- Devices can be connected in almost any wiring shape
- Strict daisy or star topology is not required
- Installation cost and time are significantly reduced
While many free topology systems operate around 9.6 kbps, FT-10 achieved 78 kbps, offering both higher speed and flexible wiring.
FT-10 is standardized as ISO/IEC 14908-3 within the LonMark protocol family.
Its real value was not only performance — but the freedom it gave system designers and installers when planning new building wiring.
The Core Challenge: Protecting Existing Wiring
When a key component is discontinued, performance improvements may be attractive.
However, in real buildings, rewiring is often the largest cost and risk factor.
Free topology wiring introduces reflections and impedance variations.
Not all communication technologies tolerate this well.
This makes direct replacement more complex than simply choosing a faster PHY.
Is There a Direct FT-10 Compatible Alternative?
Yes.
There are solutions designed to maintain compatibility with existing FT-10 networks, including:
- Babi-LON
- FetLON
These solutions implement FT-10 compatible communication, allowing continued operation without changing the physical architecture.
For projects where the primary objective is to maintain the existing LonWorks architecture with minimal change, compatibility-based approaches can be practical.
However, they typically preserve the same bandwidth and overall system structure.
They extend the current design — but do not fundamentally expand it.
Is Ethernet a Replacement Option?
Single Pair Ethernet technologies such as 10BASE-T1L are sometimes considered.
10BASE-T1L supports long cable distances and can operate in daisy-chain configurations.
However, it does not support true free topology wiring.
Structured cabling and controlled topology are still required.
In many existing FT-10 installations, wiring is branched and optimized for flexibility rather than strict topology rules.
As a result, migrating to Ethernet often requires partial or full rewiring — increasing cost and complexity.
Why Power Line Communication Technology Is a Strong Candidate
Power Line Communication (PLC) technologies are inherently tolerant of complex and irregular wiring environments.
Unlike conventional Ethernet, PLC is designed to operate over branching structures where reflections may occur.
There are two major categories:
- Narrowband PLC (e.g., G3-PLC)
- Broadband PLC (e.g., Nessum)
G3-PLC is widely used in smart meters and optimized for long-distance, low-bandwidth communication.
Modern control systems — both in buildings and in energy infrastructure — increasingly require higher throughput and faster response.
Broadband PLC technologies such as Nessum provide significantly higher bandwidth while preserving free topology capability.
As a result, Nessum is being adopted not only in building automation systems, but also in next-generation smart meters that demand fast communication for real-time grid control.
Technology Comparison
|
Feature |
FT-10 |
G3-PLC |
Nessum |
|
Topology |
Free |
Free |
Free |
|
Polarity Sensitive |
No |
No |
No |
|
Termination Required |
Yes |
No |
No |
|
Distance Between Two Nodes |
300 m |
2,000 m |
500–1,000 m |
|
Total Cable Length |
500 m |
2,000 m |
2,000 m |
|
Data Rate |
78 kbps |
~250 kbps |
~10,000 kbps |
Nessum preserves the installation flexibility of FT-10 while enabling substantially higher performance.
Standardized Evolution Within the Lon Family
FT-10 is standardized as ISO/IEC 14908-3.
Nessum is standardized as ISO/IEC 14908-8.
ISO/IEC 14908 defines the LonMark protocol stack.
Being assigned a dedicated part number within this series means Nessum is officially recognized as a standardized link layer option within the Lon ecosystem.
This is significant.
Nessum is not an external overlay technology.
It is positioned as a formal evolution path within the same ISO/IEC 14908 framework. This provides long-term interoperability assurance and protects system investment.
In addition, Nessum enables:
- Higher communication speed
- Larger and more scalable networks
- Integration with IP-based protocols such as BACnet/IP
With its Ethernet bridge capability, migration toward IP networking can occur step by step — without immediate large-scale rewiring.
Conclusion: Compatibility or Evolution?
The discontinuation of the Neuron chip creates two strategic paths for FT-10 (ISO/IEC 14908-3) systems.
Compatibility Path
FT-10 compatible solutions such as Babi-LON and FetLON allow continuation of the existing architecture with minimal structural change.
Evolution Path
Nessum (ISO/IEC 14908-8) preserves free topology wiring while expanding bandwidth, scalability, and IP readiness. The core requirement of free topology has not changed.
The key decision is whether to:
- Maintain the current system design
- Or use this transition as an opportunity to modernize while protecting existing wiring
Rather than simply replacing a discontinued chip, organizations can choose a structured, standards-based migration strategy that aligns with long-term building communication needs.
Frequently Asked Questions
What replaces LonWorks FT-10 after the Neuron chip discontinuation?
There are two approaches:
- FT-10 compatible solutions (e.g., Babi-LON, FetLON) for maintaining existing architecture
- Nessum (ISO/IEC 14908-8) for preserving free topology while enabling higher performance and future IP integration
Can existing LonWorks FT-10 wiring be reused?
Yes.
Both FT-10 compatible solutions and PLC-based technologies such as Nessum are designed to operate over free topology wiring.
Ethernet technologies such as 10BASE-T1L typically require structured topology and may require rewiring.
Is Nessum officially recognized within LonMark?
Yes.
FT-10 is defined as ISO/IEC 14908-3, and Nessum is defined as ISO/IEC 14908-8.
Both belong to the ISO/IEC 14908 series that defines the LonMark protocol stack.
Why not simply migrate to Ethernet?
Ethernet assumes structured topology and controlled cabling conditions.
Many existing free topology installations do not meet these requirements without redesign.
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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.










