ISO/IEC 14543-4-303:2026

ISO/IEC 14543-4-303
Edition 1.0 2026-06
INTERNATIONAL
STANDARD
Information technology - Home Electronic System (HES) architecture -
Part 4-303: Application protocol for electric vehicle supply equipment (EVSE)
chargers and controllers
ICS 35.020  ISBN 978-2-8327-1344-0

ISO/IEC 14543-4-303: 2026-06(en)

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CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, and abbreviated terms . 6
3.1 Terms and definitions. 6
3.2 Abbreviated terms . 8
4 Conformance . 8
5 Configuration . 8
6 Application layer . 10
6.1 General . 10
6.2 NECD objects . 10
6.3 NECD services . 11
6.4 Object-specific NECD properties . 11
6.5 Application operation . 13
6.5.1 General . 13
6.5.2 Continuous requests . 13
6.5.3 Response wait time value for controllers . 13
6.5.4 Resending a frame . 13
6.5.5 Processing object property counter . 13
6.5.6 Property values of write requests . 13
6.5.7 Property values of read requests . 14
7 Normal operation . 14
7.1 General . 14
7.2 Start-up operation . 15
7.2.1 General . 15
7.2.2 Start-up processing of NECD nodes . 15
7.2.3 Search processing . 16
7.2.4 Obtaining NECD attribute information . 16
7.2.5 Obtaining EVSE charger attribute information . 17
7.3 Occasional operation . 18
7.3.1 General . 18
7.3.2 Obtaining vehicle connection and chargeable status . 18
7.3.3 Controlling EVSE charger . 20
7.4 Fault status notification . 22
8 Remote control . 22
9 Considerations on controllers . 23
Annex A (informative) Terms and NECD protocol frame format on ISO/IEC 14543-4-3
and IEC 62394 . 24
A.1 Terms correspondence between ISO/IEC 14543-4-3 and IEC 62394 . 24
A.2 NECD protocol frame format . 24
Annex B (informative) Communication link between EVSE charger and CEM in
IEC 63380-1 . 26
Annex C (informative) Relationship between ISO/IEC 14543-4 series and the HES
gateway, based on ISO/IEC 15045 series and ISO/IEC 18012 series . 27
Bibliography . 34
Figure 1 – Relationship between IEC 62394, ISO/IEC 14543-4-3, and
ISO/IEC 14543‑4‑303 . 5
Figure 2 – Physical configuration, and the path and direction of electricity and
communication . 9
Figure 3 – NECD configurations . 9
Figure 4 – Assumed network stack. 10
Figure 5 – Summary of normal operation sequences . 15
Figure 6 – Sequence for obtaining NECD attribute information . 17
Figure 7 – Sequence of obtaining EVSE charger attribute information . 18
Figure 8 – Sequence to obtain vehicle connection and chargeable status of EVSE
charger . 19
Figure 9 – Sequence to control EVSE charger . 21
Figure 10 – Remote control . 22
Figure A.1 – NECD protocol frame format . 25
Figure B.1 – Communication link between EVSE charger and CEM in IEC 63380-1 . 26
Figure C.1 – Measurement points for AC EVSEs translated into ISO/IEC 18012-3 . 32
Figure C.2 – Measurement points for DC EVSEs translated into ISO/IEC 18012-3 . 33

Table 1 – NECD objects for EVSE chargers . 10
Table 2 – NECD objects for controllers . 11
Table 3 – NECD services . 11
Table 4 – NECD properties of device object (super class) . 11
Table 5 – NECD properties of device object . 12
Table 6 – Response wait time values for controllers . 13
Table A.1 – Terms correspondence table between ISO/IEC 14543-4-3 and IEC 62394 . 24
Table C.1 – List of the translation between ISO/IEC 14543-4-303, IEC 62394, and
HES gateway lexicon (ISO/IEC 18012‑3) supported . 27
Table C.2 – List of the translation between ISO/IEC 14543-4-303, IEC 62394, and
HES gateway lexicon (ISO/IEC 18012‑3) not supported at this time . 31

Information technology -
Home Electronic System (HES) architecture -
Part 4-303: Application protocol for electric vehicle
supply equipment (EVSE) chargers and controllers

FOREWORD
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all such patent rights.
ISO/IEC 14543-4-303 has been prepared by subcommittee 25: Interconnection of information
technology equipment, of ISO/IEC joint technical committee 1: Information technology. It is an
International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
JTC1-SC25/3321/CDV JTC1-SC25/3346A/RVC

Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
The list of all currently available parts of the ISO/IEC 14543 series, under the general title
Information technology - Home Electronic System (HES) architecture, can be found on the IEC
website and ISO website.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1, available at
www.iec.ch/members_experts/refdocs and www.iso.org/directives.

INTRODUCTION
The ISO/IEC 14543 series provides networking capability for a wide range of appliances,
equipment, sensors, etc. in the home, including lighting, heating, and cooling. This part of
ISO/IEC 14543 specifies the detailed procedures and behaviours of both electric vehicle supply
equipment (EVSE) chargers and controllers at the application level of communications based
on ISO/IEC 14543-4-3. This document specifies the message structure, sequences, and
protocol of the application layer for networked enhanced control devices (NECDs) used in the
Home Electronic System (HES). Some services are targeted for communications between
devices. Other services are exclusively reserved for management purposes. Some services can
be used for both management and run-time communications. This document is applicable for
energy management services involving EVSE chargers and related devices.
Figure 1 shows the relationship between IEC 62394, ISO/IEC 14543-4-3 and
ISO/IEC 14543-4-303. ISO/IEC 14543-4-3 specifies the message structure, sequences and
protocol for general-purpose communications used in network enhanced control devices of the
Home Electronic System (HES) Class 1. ISO/IEC 14543-4-3 provides the common interfaces
for the use-level process and the services such as energy management, remote maintenance,
and other services for easily building a system consisting of multi-vendor devices and
equipment. IEC 62394 specifies the detailed lists of control commands on NECD objects (see
ISO/IEC 14543-4-3). Annex A shows terms and NECD protocol frame format on
ISO/IEC 14543-4-3 and IEC 62394.

Application protocol:
ISO/IEC 14543-4-303
specified for each device class
Application layer
Control commands IEC 62394
NECD Protocol ISO/IEC 14543-4-3
Transport layer
Network layer
MAC layer
PHY layer
Figure 1 – Relationship between IEC 62394, ISO/IEC 14543-4-3, and ISO/IEC 14543‑4‑303
ISO/IEC 14543-4-3 is a general-purpose communications specification that applies to a variety
of devices. ISO/IEC 14543-4-3 is the basis for this document, which specifies detailed
procedures and behaviours for pre-packaged system solutions that include EVSE chargers and
related devices. The procedures and behaviours specified in this document can be used for
energy flow inside a home or energy flow between the grid and a home.
In order to enhance interoperability, it is important to specify how to implement
ISO/IEC 14543-4-3 for each device and controller at the application level such as command
sequences, timeout requirements, required combinations of acceptable commands, minimum
subset of IEC 62394 properties, etc.
This document applies to the communication link in yellow between charging station (EVSE
charger) and energy management system (EMS) as shown in Annex B.
For an EVSE that is capable of transferring electricity both from home or grid to EV and from
EV to home or grid, see ISO/IEC 14543-4-304.
1 Scope
This part of ISO/IEC 14543 specifies an application-layer protocol important for ensuring
interoperability among the products of various manufacturers regarding communications
between electric vehicle supply equipment (EVSE) chargers and controllers. It uses the network
enhanced communications device (NECD) protocol specified in ISO/IEC 14543-4-3. This
protocol is based on UDP using IPv4 or IPv6 (TCP is optional).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 62394, Service diagnostic interface for consumer electronics products and networks -
Implementation for ECHONET
ISO/IEC 14543-4-3, Information technology - Home Electronic System (HES) architecture -
Part 4-3: Application layer interface to lower communications layers for network enhanced
control devices of HES Class 1
3 Terms, definitions, and abbreviated terms
3.1 Terms and definitions
For the purposes of this document the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
– IEC Electropedia: available at https://www.electropedia.org/
– ISO Online browsing platform: available at https://www.iso.org/obp
3.1.1
controller
network enhanced control device (NECD) node that sends NECD requests (Get and SetC) to
another NECD node
Note 1 to entry: A controller in this document can be used as a part of a customer energy manager (CEM) specified
in IEC 63380-1.
Note 2 to entry: A controller in this document can be used with an energy management agent (EMA) specified in
ISO/IEC 15067-3.
3.1.2
device object
network enhanced control device (NECD) object other than a node profile object
Note 1 to entry: In this document, "device object" refers to electric vehicle charger object only.
[SOURCE: ISO/IEC 14543-4-302:2023, 3.1.3, modified – In Note 1 to entry, "storage battery"
has been replaced with "electric vehicle charger".]
3.1.3
electric vehicle
EV
vehicle that is powered by an electric motor that draws electricity from a battery and is capable
of being charged from an external source
Note 1 to entry: In this document, "electric vehicle" refers to both a vehicle that is only powered by an electric motor
that draws electricity from a battery and a vehicle that is powered by an electric motor that draws electricity from a
battery and by an internal combustion engine.
Note 2 to entry: In this document, "electric vehicle" refers to both a vehicle that contains a device that converts
alternating current (AC) voltage to direct current (DC) voltage (e.g. inverter) and a vehicle that does not contain a
device that converts AC voltage to DC voltage.
3.1.4
electric vehicle supply equipment
EVSE
device that transfers electricity between electric vehicle and home or grid
Note 1 to entry: In this document, "electric vehicle supply equipment" refers to both a device that contains a device
that converts alternating current (AC) voltage to direct current (DC) voltage (e.g. inverter) and a device that does not
contain a device that converts AC voltage to DC voltage.
Note 2 to entry: In this document, "electric vehicle supply equipment" refers to a device that supports primarily
single-family residential applications.
3.1.5
electric vehicle supply equipment charger
EVSE charger
electric vehicle supply equipment that includes a communications interface of NECD protocol
and is capable of managing the transfer of electricity from home or grid to electric vehicle (EV)
and includes a communications interface to receive network enhanced control device (NECD)
messages
Note 1 to entry: In this document, "electric vehicle supply equipment charger" refers primarily to an EVSE that is
not capable of transferring electricity from an EV to home or grid using the NECD protocol.
3.1.6
NECD protocol
protocol used in network enhanced control device (NECD) communications
[SOURCE: ISO/IEC 14543-4-302:2023, 3.1.5]
3.1.7
node profile
description of objects implemented in each node
[SOURCE: ISO/IEC 14543-4-302:2023, 3.1.6]
3.1.8
remote control
control from outside the home
[SOURCE: ISO/IEC 14543-4-302:2023, 3.1.9]
3.1.9
response wait time
time between a controller request to an electric vehicle supply equipment (EVSE) charger and
the response from an electric vehicle supply equipment charger
3.1.10
super class
properties that are inherited and implemented in all device objects
[SOURCE: ISO/IEC 14543-4-302:2023, 3.1.11]
3.2 Abbreviated terms
AC alternating current
DC direct current
DNOJ destination NECD object
EV electric vehicle
EVSE electric vehicle supply equipment
IP internet protocol
NDATA NECD data
NDT NECD property value data
NECD network enhanced control device
NHD NECD header
NPC NECD property code
NSV NECD service
OPC object property counter
PDC property data counter
SNOJ source NECD object
TID transaction ID
UDP user datagram protocol
4 Conformance
EVSE chargers and controllers of HES Class 1 that claim conformance to this document shall:
– send, receive and process sequences and procedures as specified in Clause 7.
– provide application services and properties specified in 6.2, 6.3, and 6.4 as needed by EVSE
chargers and controllers for which the application is intended.
5 Configuration
This document is necessary for ensuring interoperability between the products of different
manufacturers in connection with application communications between EVSE chargers and
controllers, using the NECD protocol as an application protocol via UDP (TCP) and IPv6
communications.
Figure 2 shows the physical configuration in this document and the path and direction of
electricity and communication. As shown in Figure 2, this document considers the electricity
that is transferred from home or grid to EV only. This document does not specify any
requirement about the connector, data, and electricity between electric vehicle (EV) and EVSE.
Any type of connector, data, and electricity can be used between EV and EVSE that are referred
to in this document.
Figure 2 – Physical configuration, and the path and direction
of electricity and communication
Figure 3 shows the NECD configurations assumed in this document.

a
"Electric vehicle charger class object" is a device object specified in IEC 62394.
Figure 3 – NECD configurations
The upper illustration in Figure 3 shows the case where a single device object is installed in a
single node. The lower illustration shows the case where multiple device objects are installed
in a single node. The latter case occurs when multiple EVSE charger units are attached to a
single communications unit. In this case, there are multiple electric vehicle charger class objects
in a single EVSE charger node (i.e. at a single IP address). Controllers shall support nodes that
configure multiple device objects in a single node.
Controllers shall be capable of handling multiple nodes and objects. The maximum number of
nodes and objects to be handled is implementation-dependent on the controllers. In the
environment where multiple controllers exist on the same network, an EVSE charger shall
respond to the latest command from any controller.
Figure 4 shows the assumed network stack for operating the NECD protocol in this document.
NECD protocol operation is assumed as an application protocol on UDP(TCP) and IPv6.
TCP installation is optional. As a rule, the stack uses IPv6; however, IPv4 is allowed depending
on the market trends for migration from IPv4 to IPv6.

ISO/IEC 14543-4-303
Application layer IEC 62394
ISO/IEC14543-4-3
Transport layer UDP(TCP)
Network layer IPv6 or IPv4
a
(Adaptation layer) (6LoWPAN )
MAC layer (No specific MAC layer assumed)
PHY layer (No specific PHY layer assumed)

a
Depends on transmission media using IPv6.
Figure 4 – Assumed network stack
Connection processing specific to each lower layer communications medium that is necessary
in advance of the start of NECD communications is out of the scope of this document. In this
document, application communications using the NECD protocol are specified on the
assumption that connection processing specific to those communications media is complete.
6 Application layer
6.1 General
The NECD protocol shall be used at the application layer. All nodes that conform to this
document shall support all mandatory functions specified in ISO/IEC 14543-4-3.
6.2 NECD objects
EVSE chargers shall have the NECD objects shown in Table 1. Controllers shall have the NECD
objects shown in Table 2.
Table 1 – NECD objects for EVSE chargers
Class group
NECD object Class code Class name Instance code
code
0x02 0xA1 Electric vehicle charger 0x01 to 0x7F
EVSE charger
0x0E 0xF0 Node profile 0x01
NOTE 1 Instance code 0x00 is designated to specify all instances of the same class in a node.
Table 2 – NECD objects for controllers
Class group
NECD object Class code Class name Instance code
code
0x05 0xFF Controller 0x01 to 0x7F
Controller
0x0E 0xF0 Node profile 0x01
NOTE 2 Instance code 0x00 is designated to specify all instances of the same class in a node.
6.3 NECD services
EVSE chargers and controllers shall support the NECD services shown in Table 3.
Table 3 – NECD services
NSV code NECD service content Symbol Sender
0x51 Property value write "response-not-possible" response SetC_SNA EVSE charger
0x52 Property value read "response-not-possible" response Get_SNA EVSE charger
0x61 Property value write request (response required) SetC Controller
0x62 Property value read request Get Controller
0x71 Property value write response Set_Res EVSE charger
0x72 Property value read response Get_Res EVSE charger
0x73 Property value notification INF Controller and
EVSE charger
6.4 Object-specific NECD properties
EVSE chargers shall install the NECD properties of a device object shown in Table 4 and
Table 5. NECD properties of a node profile object shall support at least the mandatory
properties.
Controllers shall send requests to the device object properties shown in Table 4 and Table 5.
Table 4 – NECD properties of device object (super class)
Access rule
Announcement at
Property name NPC Units Remarks
status change
Get Set
Installation location 0x81 － M M M
Standard version information 0x82 － M － －
Identification number 0x83 － O － －
Fault status 0x88 － M － M
Manufacturer code 0x8A － M － －
Status change announcement
－ － －
0x9D M
property map
Set property map 0x9E － M － －
Get property map 0x9F － M － －
M: mandatory, O: optional, －: not supported

Table 5 – NECD properties of device object
Access rule
Announcement at
Property name NPC Units Remarks
status change
Get Set
Operation status 0x80 － M － M
a
Rated charge capacity 0xC5 W M － －

Vehicle connection and chargeable
0xC7 － M － M
status
Charger type 0xCC － M － －
b
－ － －
Vehicle connection confirmation 0xCD M

Chargeable capacity of vehicle
a, c
0xCE Wh M － －
mounted battery
Remaining chargeable capacity of
a, c
0xCF Wh M － －
vehicle mounted battery
Used capacity of vehicle-mounted
a, c, e, f
0xD0 Wh M － －
battery 1
Operating mode setting 0xDA － M M M
Remaining stored electricity of vehicle-
a, d, e
0xE2 Wh M － －
mounted battery 1
Remaining stored electricity of vehicle-
d, e
0xE4 % M － －
mounted battery 3
Vehicle ID 0xE6 M － －
M: mandatory, －: not supported
a
These properties are calculated as AC.
b
This property is mandatory only when property value of "Charger type" property [0xCC] is "DC_type AA
(charging only)" (0x21).
c
These properties are mandatory only when applicable information is provided by the EV that connects to the
EVSE charger. When the EVSE charger cannot reply, the EVSE charger shall reply Get_SNA [0x52].
d
One of them is mandatory when applicable information is provided by the EV that connects to the EVSE
charger.
e
The number at the end of the property name (1 or 3) does not express the difference of the physical battery
but expresses the difference of the unit. "1" is expressed in watt-hours (Wh) and "3" is expressed as a
percentage (%).
f
"Used capacity" is the same as "useable capacity".

The details of the properties shown in Table 4 and Table 5 are specified in IEC 62394 "Electric
vehicle charger class specifications". If a discrepancy between IEC 62394 and this document
exists, the description in this
...