Overview of the ECHONET Lite specifications

ECHONET Lite is a communication specification that enables resource-saving devices (such as sensors, home appliances, and facility-related equipment) to support IoT and realizes energy management service and remote maintenance service. By adopting common specifications for communication specifications and commands for devices, it is possible to build a system in a multi-vendor environment. The following figure shows the structure of ECHONET Lite specifications.

The main features of the ECHONET Lite that realizes IoT for resource-saving equipment and realizes interconnection between multiple vendors are shown below.

(1)　Various existing standard transmission media can be used

The scope specified in ECHONET Lite is L5 and higher in the OSI Reference Model and does not depend on lower-layer communication specifications. The communication address specifies recipients by using an IP address or MAC address of transmission media. Therefore, it is possible to select a reasonable transmission media source from the market based on various requirements, such as services and applications.

(2)　Applicable for a wide range of appliances for homes, small and medium‐sized buildings and stores

Since its establishment in 1997, ECHONET Consortium has defined and expanded control commands that model the diverse programs and data groups of various devices as device objects.

We have defined device objects for more than 120 models so far, including sensors, energy-saving devices such as air conditioners and lighting, energy-storing devices such as storage batteries and heat-pump water heaters, energy-generating devices such as solar power generators and fuel cells, measurement devices such as smart meters, and commercial devices such as commercial-use package air conditioners and showcases. Note that the device objects are classified into seven different groups (class groups) according to their use.

(3)　Further interoperability improvement for key devices

The ECHONET Lite specifications have become general-purpose specifications that can be applied to all over 110 types of devices thanks to achieve a high level of interoperability by conducting standard conformity certification tests. The ECHONET Consortium has defined more than ten types of devices as key devices, including home air conditioners, storage batteries, solar power generation, commercial-use package air conditioners, and smart meters (high/low voltage). In order to achieve a higher level of interoperability for these devices, the ECHONET Consortium has formulated the application communication interface specifications (AIF specifications) which define the specific usage of ECHONET Lite at the application level of each device. For example, the AIF specification defines the following items:

• Installed device objects
• Combination of supported properties
• Timeout after sending a request until receiving a response
• Sequence assuming concrete use case

The reliability of AIF specification certification testing is ensured by conducting standard conformity tests by a third party approved by the ECHONET Consortium.

(4)　Enables linkage with cloud services

It is important to study overall system architecture to study communication specifications. When we formulated the ECHONET Lite communication specifications, we designed an architecture which set controllers or similar devices which have gateway functions between various internet-based services and devices installed at local environment such as ordinary homes. The figure below shows an example system configuration.

Because the system above can be built, specifications study and development in services and devices can be done respectively and parallelly. This enables us to expect services to be provided not only by device manufacturers but also by various service providers.