Metasys N2 Product Family
Metasys N2 Product Family Overview
The Metasys N2 product family represents a large installed base of legacy building automation controllers and field devices originally deployed as part of Johnson Controls Metasys systems. The N2 protocol is a proprietary, RS-485 based communication protocol that was widely used for supervisory control and data acquisition in commercial and institutional buildings for many years.
Although newer Metasys systems have transitioned to BACnet-based architectures, many facilities continue to operate N2 devices due to their long service life, proven reliability, and the cost associated with wholesale system replacement. As a result, understanding the Metasys N2 product family remains highly relevant for system upgrades, phased migrations, and protocol integration projects.
The document shown below provides a visual reference of the Metasys N2 product family, including controllers, supervisory components, and associated field hardware. These images are commonly used by engineers and technicians to identify installed equipment during site surveys, retrofit planning, and integration work.
For copyable and searchable text, please open the original reference as a PDF document here .
Why the Metasys N2 Product Family Still Matters
N2 devices are still found in thousands of active installations worldwide, particularly in large campuses, hospitals, government buildings, and industrial facilities. These systems often control critical HVAC, lighting, and environmental processes, making immediate replacement impractical or risky.
Common modernization strategies include:
- Integrating N2 controllers into BACnet/IP supervisory systems
- Replacing legacy N2 supervisors while retaining field controllers
- Gradually migrating N2 devices to BACnet while maintaining system uptime
- Using protocol gateways to expose N2 points to third-party BMS platforms
In all of these cases, accurate identification of the installed Metasys N2 hardware is a prerequisite. The visual reference below helps confirm device models, generations, and form factors encountered in the field.
Metasys N2 Product Family Reference Images
The following images are extracted from the original Metasys N2 family documentation and presented here for quick reference. They show representative products and groupings used throughout the lifecycle of Metasys N2 deployments.
These images are particularly useful when:
- Performing site audits and documenting existing control hardware
- Determining compatibility with N2-to-BACnet gateways
- Planning phased upgrades or controller replacements
- Supporting troubleshooting and maintenance activities
Integration and Modernization Considerations
When integrating Metasys N2 devices into modern building automation systems, several technical factors must be considered. N2 is a master-slave protocol with strict timing requirements, and successful integration depends on accurate device modeling, correct baud rate configuration, and stable RS-485 physical layer design.
Protocol gateways are commonly used to expose N2 points as BACnet objects, allowing newer BMS platforms to read, write, and trend legacy controller data. In these scenarios, the gateway effectively becomes a protocol translator and must correctly represent the behavior and limitations of the original N2 devices.
Proper documentation of the existing N2 device inventory—using references like the images above—reduces integration risk and helps ensure predictable system behavior after migration.
Frequently Asked Questions (FAQ)
What is the Metasys N2 protocol?
Metasys N2 is a proprietary RS-485 communication protocol developed by Johnson Controls for use with Metasys field controllers and supervisory devices. It predates widespread BACnet adoption and is now considered a legacy protocol.
Are Metasys N2 devices still supported?
While many N2 products are no longer actively manufactured, they are still widely deployed and maintained in existing installations. Support often focuses on integration and migration rather than new deployments.
Can Metasys N2 devices be integrated into BACnet systems?
Yes. N2-to-BACnet gateways are commonly used to expose N2 data points as BACnet objects, enabling integration with modern BACnet/IP supervisory systems.
Why use images instead of text lists?
Visual references are often faster and more reliable for field identification, especially when dealing with older hardware where labels may be missing or partially damaged.
Is this page a replacement for the official documentation?
No. This page provides a convenient visual reference. For authoritative specifications and copyable text, always consult the linked PDF documentation.