SIST EN 13757-7:2025
(Main)Communication systems for meters - Part 7: Transport and security services
Communication systems for meters - Part 7: Transport and security services
This document specifies transport and security services for communication systems for meters, sensors, and actuators, used to provide metering services.
This document specifies secure communication capabilities by design and supports the building of a secure system architecture.
This document is applicable to the protection of consumer data to ensure privacy.
This document is intended to be used with the lower layer specifications determined in the relevant parts of the EN 13757 series.
Kommunikationssysteme für Zähler - Teil 7: Transport- und Sicherheitsdienste
Dieses Dokument legt die Transport- und Sicherheitsdienste für Kommunikationssysteme für Zähler, Sensoren und Aktoren fest, die zur Bereitstellung von Messdienstleistungen verwendet werden.
Dieses Dokument legt sichere Kommunikationsfähigkeiten nach Design fest und unterstützt den Aufbau einer sicheren Systemarchitektur.
Dieses Dokument ist anwendbar für den Schutz der Verbraucherdaten zur Sicherung des Datenschutzes.
Dieses Dokument soll mit den in den relevanten Teilen der Normenreihe EN 13757 festgelegten Spezifikationen der unteren Schicht verwendet werden.
Systèmes de communication pour compteurs - Partie 7 : Services de transport et de sécurité
Le présent document spécifie les services de transport et de sécurité pour les systèmes de communication pour compteurs, capteurs et actionneurs, utilisés pour fournir des services de comptage.
Le présent document spécifie des fonctionnalités de communication sécurisées par conception et supporte la réalisation d’une architecture de systèmes sécurisés.
Le présent document s’applique à la protection des données relatives aux consommateurs afin d’assurer la confidentialité.
Le présent document est destiné à être utilisé avec les spécifications relatives aux couches inférieures déterminées dans les parties correspondantes de la série EN 13757.
Komunikacijski sistemi za merilnike - 7. del: Prevoz in varnostne službe
Ta dokument določa prevoz in varnostne službe za komunikacijske sisteme za merilnike, senzorje in aktivatorje, ki se uporabljajo za zagotavljanje storitev merjenja. Ta dokument določa zasnovo z zmožnostjo zagotavljanja varne komunikacije in podpira izgradnjo sistema z varno arhitekturo. Ta dokument se uporablja za zaščito potrošniških podatkov za ohranjanje zasebnosti. Ta dokument je namenjen uporabi s specifikacijami spodnje plasti, ki so določene v ustreznih delih skupine standardov EN 13757.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-junij-2025
Komunikacijski sistemi za merilnike - 7. del: Prevoz in varnostne službe
Communication systems for meters - Part 7: Transport and security services
Kommunikationssysteme für Zähler - Teil 7: Transport- und Sicherheitsdienste
Systèmes de communication pour compteurs - Partie 7 : Services de transport et de
sécurité
Ta slovenski standard je istoveten z: EN 13757-7:2025
ICS:
33.200 Daljinsko krmiljenje, daljinske Telecontrol. Telemetering
meritve (telemetrija)
35.100.10 Fizični sloj Physical layer
35.100.20 Podatkovni povezovalni sloj Data link layer
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 13757-7
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2025
EUROPÄISCHE NORM
ICS 33.200; 35.100.10; 35.100.20; 91.140.50 Supersedes EN 13757-7:2018
English Version
Communication systems for meters - Part 7: Transport and
security services
Systèmes de communication pour compteurs - Partie 7 Kommunikationssysteme für Zähler - Teil 7:
: Services de transport et de sécurité Transport- und Sicherheitsdienste
This European Standard was approved by CEN on 24 February 2025.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13757-7:2025 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
Introduction . 6
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
4 Abbreviations and symbols . 11
4.1 Abbreviations . 11
4.2 Symbols . 13
5 Layer model . 13
5.1 M-Bus Layers . 13
5.2 The CI-field principle . 14
6 Authentication and Fragmentation Sublayer (AFL) . 18
6.1 Introduction . 18
6.2 Overview of the AFL-Structure . 19
6.3 Components of the AFL. 20
6.3.1 AFL Length Field (AFL.AFLL) . 20
6.3.2 AFL Fragmentation Control Field (AFL.FCL) . 20
6.3.3 AFL Message Control Field (AFL.MCL) . 20
6.3.4 AFL Key Information-Field (AFL.KI) . 21
6.3.5 AFL Message counter field (AFL.MCR) . 22
6.3.6 AFL MAC-field (AFL.MAC) . 22
6.3.7 AFL Message Length Field (AFL.ML) . 22
7 Transport Layer (TPL) . 23
7.1 Introduction . 23
7.2 Structure of none TPL header . 23
7.3 Structure of short TPL header . 23
7.4 Structure of long TPL header . 24
7.5 CI-field dependent elements . 24
7.5.1 Identification number . 24
7.5.2 Manufacturer identification . 25
7.5.3 Version identification . 25
7.5.4 Device type identification . 25
7.5.5 Access number . 27
7.5.6 Status byte in meter messages . 29
7.5.7 Status byte in partner messages . 30
7.5.8 Configuration field . 31
7.6 Configuration field dependent structure. 32
7.6.1 General . 32
7.6.2 Configuration field extension . 32
7.6.3 Optional TPL-header fields . 32
7.6.4 Optional TPL Trailer fields . 33
7.6.5 Partial encryption . 33
7.7 Security Mode specific TPL-fields. 33
7.7.1 Shared subfields of configuration field and configuration field extension . 33
7.7.2 Configuration field of Security Mode 0 . 36
7.7.3 Configuration field of Security Modes 2 and 3 . 37
7.7.4 Configuration field of Security Mode 5 . 38
7.7.5 Configuration field of Security Mode 7 . 39
7.7.6 Configuration field of Security Mode 8 . 41
7.7.7 Configuration field of Security Mode 9 . 43
7.7.8 Configuration field of Security Mode 10 . 45
8 Management of lower layers . 47
8.1 General . 47
8.2 Switching baud rate for M-Bus Link Layer according to EN 13757-2 . 47
8.3 Address structure if used together with the wireless Data Link Layer according to
EN 13757-4 . 47
8.4 Selection and secondary addressing . 47
8.5 Generalized selection procedure . 48
8.6 Searching for installed slaves . 49
8.6.1 Primary addresses . 49
8.6.2 Secondary addresses . 49
8.6.3 Wildcard searching procedure . 49
9 Security Services . 50
9.1 General . 50
9.2 Message counter. 51
9.2.1 Overview . 51
9.2.2 Message counter C transmitted by the meter . 52
M
9.2.3 Message counter C transmitted by the communication partner . 52
CP
9.2.4 Message counter C’ received by the meter . 52
CP
9.2.5 Message counter C’ and C” received by the communication partner . 53
M M
9.3 Authentication methods in the AFL . 53
9.3.1 Overview . 53
9.3.2 Authentication method AES-CMAC-128 . 54
9.3.3 Authentication method AES-GMAC-128 . 54
9.4 Encryption and authentication methods in the TPL . 55
9.4.1 Overview about TPL-security mechanisms . 55
9.4.2 Manufacturer specific security mechanism (Security Mode 1) . 56
9.4.3 Security mechanism DES-CBC (Security Mode 2 and 3) . 56
9.4.4 Security mechanism AES-CBC-128 (Security Mode 5) . 57
9.4.5 Security mechanism AES-CBC-128 (Security Mode 7) . 58
9.4.6 Security mechanism AES-CTR-128 (Security Mode 8) . 59
9.4.7 Security mechanism AES-GCM-128 (Security Mode 9) . 60
9.4.8 Security mechanism AES-CCM-128 (Security Mode 10) . 63
9.5 Reaction to security failure . 65
9.6 Key derivation. 66
9.6.1 General . 66
9.6.2 Key derivation function A . 66
9.7 Key Exchange . 67
Annex A (normative) Security Information Transfer Protocol . 68
Annex B (informative) Message counter example . 86
Bibliography . 90
European foreword
This document (EN 13757-7:2025) has been prepared by Technical Committee CEN/TC 294
“Communication systems for meters”, the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by October 2025, and conflicting national standards shall
be withdrawn at the latest by October 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 13757-7:2018.
— support of sensor devices and alarm devices;
— reduction of device types for thermal energy meter;
— support of MBAL acc. to EN 13757-8;
— introduction of a content definition for the subfield Content index in the Configuration field;
— application of a separate message counter for each Key ID used in TPL;
— update of the definition of the SITP in Annex A like adding DSI 23 and withdrawing DSI 30 .
h h
EN 13757 is currently composed with the following parts:
— Communication systems for meters — Part 1: Data exchange;
— Communication systems for meters — Part 2: Wired M-Bus communication;
— Communication systems for meters — Part 3: Application protocols;
— Communication systems for meters — Part 4: Wireless M-Bus communication;
— Communication systems for meters — Part 5: Wireless M-Bus relaying;
— Communication systems for meters — Part 7: Transport and security services;
— Communication systems for meters — Part 8: Adaptation Layer;
— CEN/TR 17167, Communication systems for meters — Accompanying TR to EN 13757-2, −3 and −7,
Examples and supplementary information.
This document is read in conjunction with CEN/CLC/ETSI/TR 50572 [4].
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
This document falls under the Mandate EU M/441 “Standardisation mandate to CEN, CENELEC and ETSI
in the field of measuring instruments for the development of an open architecture for utility meters
involving communication protocols enabling interoperability” by providing the relevant definitions and
methods for meter data transmission on application layer level. The M/441 Mandate is driving significant
development of standards in smart metering.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
Introduction
This document belongs to the EN 13757 series, which covers communication systems for meters.
EN 13757-1 contains generic descriptions and a communication protocol. EN 13757-2 contains a
physical and a Link Layer for twisted pair based Meter-Bus (M-Bus). EN 13757-3 contains detailed
description of the application protocols especially the M-Bus Protocol. EN 13757-4 describes wireless
communication (often called wireless M-Bus or wM-Bus). EN 13757-5 describes the wireless network
used for repeating, relaying and routing for the different modes of EN 13757-4. EN 13757-7 describes
transport mechanism and security methods for data. The Technical Report CEN/TR 17167 contains
informative annexes from EN 13757-2, EN 13757-3 and EN 13757-7.
These upper M-Bus protocol layers can be used with various Physical Layers and with Data Link Layers
and Network Layers, which support the transmission of variable length binary transparent messages.
Frequently, the Physical and Link Layers of EN 13757-2 (twisted pair) and EN 13757-4 (wireless) as well
as EN 13757-5 (wireless with routing function) or the alternatives described in EN 13757-1 are used.
These upper M-Bus protocol layers have been optimized for minimum battery consumption of meters,
especially for the case of wireless communication, to ensure long battery lifetimes of the meters.
Secondly, it is optimized for minimum message length to minimize the wireless channel occupancy and
hence the collision rate. Thirdly, it is optimized for minimum requirements towards the meter processor
regarding requirements of RAM size, code length and computational power.
An overview of communication systems for meters is given in EN 13757-1, which also contains further
definitions.
This document concentrates on the meter communication. The meter communicates with one (or
occasionally several) fixed or mobile communication partners which again might be part of a private or
public network. These further communication systems might use the same or other application layer
protocols, security, privacy, authentication, and management methods.
To facilitate common communication systems for CEN-meters (e.g. gas, water, thermal energy and heat
cost allocators) and for electricity meters, in this document occasionally electricity meters are mentioned.
All these references are for information only and are not standard requirements. The definition of
communication standards for electricity meters (possibly by a reference to CEN standards) remains
solely in the responsibility of CENELEC.
NOTE 1 CEN/TR 17167:2023, Annex C specifies how parts of this standard and of EN 13757-2 and EN 13757-4
can be used to implement smart meter functionalities. Similar functionalities could also be implemented using other
Physical and Link Layers.
NOTE 2 For information on installation procedures and their integration in meter management systems, see
CEN/TR 17167:2023, Annex D.
The operator of a smart metering network needs to secure the network to ensure the data protection and
data privacy of the consumer (see EC-Recommendation C1342 (2012)). Securing a system requires a
security policy, which addresses in general all constraints on functions, information flow between
functions, access by external systems and threats, including software and access to data by third persons
from an organizational viewpoint.
The security policy is under the responsibility of organizations according to their business processes. The
major elements of a security policy, in combination with rules, will determine the overall security that is
achieved. The security policy defines goals and elements of the system to be supported by organizational
policy and technical implementations of security services. Establishing and executing security policies
are outside the scope of this document; however, this document provides security services supporting
those policies when implemented.
A security concept refers mainly to an architectural model, which represents data flows between role-
based data processing functions. Requirements for the security concept result from the overall security
objectives in combination with the derived security services and best practice. This document provides a
set of security services allowing the design of a secure system, which is likely to resist attacks within the
lifetime of the meter.
The limitation to symmetrical cipher methods for data transmission allow energy and memory efficient
solutions. This is advantageous for long-term battery operated meters. It enables integration of
unidirectional meter communication as well. Services like key derivation and key distribution solves the
conflict between short key lifetime and long lifetime of a meter.
1 Scope
This document specifies transport and security services for communication systems for meters, sensors,
and actuators, used to provide metering services.
This document specifies secure communication capabilities by design and supports the building of a
secure system architecture.
This document is applicable to the protection of consumer data to ensure privacy.
This document is intended to be used with the lower layer specifications determined in the relevant parts
of the EN 13757 series.
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.
EN 13757-3:2025, Communication systems for meters — Part 3: Application protocols
EN 13757-4:2019, Communication systems for meters — Part 4: Wireless M-Bus communication
EN 13757-5, Communication systems for meters — Part 5: Wireless M-Bus relaying
NIST/SP 800-38A:2001-12, Recommendation for Block Cipher Modes of Operation: Methods and
Techniques
NIST/SP 800-38B:2005-05, Recommendation for Block Cipher Modes of Operation: CMAC Mode for
Authentication
NIST/SP 800-38C:2004-05, Recommendation for Block Cipher Modes of Operation: The CCM Mode for
Authentication and Confidentiality
NIST/SP 800-38D:2007-11, Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode
(GCM) and GMAC
3 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:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
3.1
application data
data used and/or generated by the metering process such as register values, tariffs, conversion factors or
data used to control the metering process respectively the output or additional information
3.2
application protocol
protocol for the coding of application data
Note 1 to entry: Application protocols are specified in EN 13757-3.
3.3
authenticity
property that data originated from its purported source
[SOURCE: NIST/SP 800-38F:2012-12, NIST/SP 800-38C:2004-05]
3.4
byte
octet of bits
3.5
confidentiality
property that information is not made available or disclosed to unauthorized individuals, entities, or
processes
[SOURCE: ISO 7498-2:1989, 3.3.16]
3.6
data integrity
integrity
property that data has not been altered or destroyed in an unauthorized manner
[SOURCE: ISO 7498-2:1989, 3.3.21 – modified: “integrity” has been added as an alternative term]
3.7
datagram
unit of data transferred from source to destination
Note 1 to entry: In previous versions of EN 13757-3 datagram was called telegram.
3.8
ephemeral key
key used to encrypt or decrypt a single message or for a limited time or a limited amount of data
3.9
fragment
datagram of a fragmented message
3.10
hex-ASCII
base-16 numbers encoded as ASCII characters (‘0’−‘9’, ‘A’−‘F’)
[SOURCE: ANSI X9 TR-31:2010]
3.11
initialization vector
number used as starting point for the encryption of data sequences in order to increase the security by
introducing additional cryptographic variance and to synchronize cryptographic equipment
3.12
key counter
unique counter used in the Security Information Transfer Protocol to identify a secured end to end
transferred command and response
3.13
key derivation
technique by which a (potentially large) number of keys are generated (“derived”) from a single initial
key and non-secret variable data with each resulting key using a non-reversible process
3.14
message
functional set of data transferred from source to destination
Note 1 to entry: A message can consist of one or more datagrams.
3.15
message counter
unique counter used in AFL or TPL to identify a secured message
3.16
meter
measuring device for water or energy consumption, including sensors or actuators used to provide
metering services
Note 1 to entry: Meter is in general understood as including metrological devices, sensors, and actuators.
Note 2 to entry: Combination of the term meter in combination with “electricity”, “water”, “gas”, “thermal energy”,
“heat/cooling” is to be considered as a metrological device.
3.17
metrological device
measuring device for water or energy consumption, excluding sensors or actuators used to provide
metering services
EXAMPLES electricity meter, water meter, gas meter, thermal energy meter, heat cost allocator
3.18
persistent key
cryptographic key which needs to be kept for a prolonged period
3.19
security mechanism
mode of operation of a (symmetric) cryptographic algorithm
Note 1 to entry: The security mechanism is identified by the Security Mode.
3.20
Security Mode
mode number in configuration field identifying a set of applied security mechanisms
3.21
security service
authenticity, confidentiality and data integrity
Note 1 to entry: Security services are provided by security mechanisms.
3.22
sublayer
subdivision of a layer
[SOURCE: EN ISO/IEC 7498-1:1995, 5.2.1.4]
3.23
TPL-padding
fill bytes added in TPL to fill up application data to the requested size for a block cipher
3.24
wrapper key
(symmetric) key that determines the wrapping and unwrapping functions of a wrapping mechanism
3.25
wrapping mechanism
(symmetric) key authenticated encryption mechanism that is intended for the protection of
cryptographic keys and other specialized data
4 Abbreviations and symbols
4.1 Abbreviations
ACC-DMD Access Demand
ACC-NR Access – No Reply
ACK Acknowledge [EN 13757-2/EN 13757-4]
AES Advanced Encryption Standard
AFL Authentication and Fragmentation Sublayer
APDU Application Protocol Data Unit
APL Application Layer
ASCII American Standard Code for Information Interchange
BCD Binary Coded Decimal numbers
BCF Block control field of SITP structure, coding the usage of command or response
BID Block identification number of SITP structure
BL Block length of SITP structure
CBC Cipher Block Chaining; (AES mode of operation)
CCM Counter mode encryption algorithm with CBC-MAC (AES mode of operation)
CF Configuration Field
CFE Configuration Field Extension
CI Control Information field
CMAC Cipher-based MAC [NIST/SP 800-38B]
CNF-IR Confirm Installation Request
CTR Counter Mode encryption algorithm (AES mode of operation)
DES Data Encryption Standard
DIF Data Information Field
DLL Data Link Layer
DLMS Device Language Message Specification
DSI Data structure identifier, part of block parameter structure inside SITP
DSH Data structure header, part of block parameter structure inside SITP
DSH1 Byte one of DSH
DSH2 Byte two of DSH
ELL Extended Link Layer
GCM Galois/Counter Mode, an algorithm for authenticated encryption with associated data
(AES mode of operation)
GMAC a specialization of GCM for generating a message authentication code (MAC) on data that
is not encrypted
ICV Integrity check value, part of a wrapped data structure in SITP
IV Initialization Vector
LSB Least Significant Byte
LSBit Least Significant Bit
MAC Message Authentication Code
NOTE MAC is in other standards also used as an acronym for Media Access Control for data
communication at the Physical Layer.
MBAL M-Bus Adaptation layer [EN 13757-8]
MK Message Key (persistent)
MLI Message Length Indicator, part of a wrapped data structure in SITP
MSB Most Significant Byte
MSBit Most Significant Bit
NWL Network Layer
OBIS Object Identification System (EN 62056-61)
PID Protocol identifier field, part of wrapped data structure in SITP
REQ-UD Request User Data (class 1 or 2) [EN 13757-2/EN 13757-4]
RSP-UD Respond User Data [EN 13757-2/EN 13757-4]
RSSI Received Signal Strength Indicator
SITP Security Information Transfer Protocol
SND-IR Send Installation Request [EN 13757-4]
SND-NKE Send Link Reset [EN 13757-2/EN 13757-4]
SND-NR Send – No Reply [EN 13757-4]
SND-UD Send User Data [EN 13757-2/EN 13757-4]
SND-UD2 Send User Data 2 [EN 13757-2/EN 13757-4]
SND-UD3 Send User Data 3 [EN 13757-4]
TPDU Transport Protocol Data Unit
TPL Transport Layer
VIF Value Information Field
VIFE Value Information Field Extensions
4.2 Symbols
Hexadecimal numbers are designated by a following “ ”
h .
Binary numbers are designated by a following “ ”.
b
Decimal numbers have no suffix.
The concatenation of fields is indicated by the symbol “||”. E. g. 12 || 34 results in 1234 .
h h h
5 Layer model
5.1 M-Bus Layers
The M-Bus covers several communication layers. The Physical Layer and the Data Link Layer are
mandatory for all type of communications. The structure of these two layers depends on the
communication media (wired M-Bus (EN 13757-2) or wireless M-Bus (EN 13757-4 and EN 13757-5)).
The presence of the other layers depends on:
— communication media (wired/wireless M-Bus, Radio mode),
— message type (e.g. REQ-UD2 or RSP-UD),
— message length (fragmentation required),
— selected type of Security Mode.
Table 1 shows the applicable layers, their order and the related part of this standard series in which they
are described. The upper protocol layers AFL, TPL and APL are specified in this document.
Table 1 — Order of M-Bus Layer
OSI model
Colour
Declared by Related part of this
Abbreviation Layer
b
CI-field standard series
codes
Layer
EN 13757-1/ Application
a
APL Application Layer Orange
EN 13757-3 Presentation
TPL Transport Layer yes EN 13757-7 Green
Session
Authentication and
Transport
AFL Fragmentation yes EN 13757-7 Purple
Sublayer
NWL Network Layer yes EN 13757-5 Pink Network
ELL Extended Link Layer yes EN 13757-4 Blue
Data Link
Light
DLL Data Link Layer no EN 13757-2/EN 13757-5
blue
Light
PHY Physical Layer no EN 13757-2/EN 13757-5 Physical
yellow
a
The APL is not introduced by a dedicated CI-field but declared by CI-field of the TPL.
b
These colour codes are applied in examples given in CEN/TR 17167.
NOTE The relation between the M-Bus Layers and the OSI Layers is not a one-to-one relation. The OSI Data
Link Layer is provided by two M-Bus Layers (DLL and ELL). The functionality of the OSI Layers 4 and 5 are
represented by the M-Bus Layers AFL and TPL. The functionality of the OSI Layers 6 and 7 are represented by the
M-Bus Layers APL.
5.2 The CI-field principle
All layers between the DLL and the APL are introduced by a CI-field (control information field). These CI-
fields declares the structure of the following layers.
The layers ELL and NWL do not provide a dedicated length information. The length of these layers and
the start position of the next layer shall be according to the specification of EN 13757-4 or EN 13757-5,
as applicable.
The AFL has a variable structure. It declares the length of this layer by a dedicated length field.
The Transport Layer and the Application Layer uses a shared CI-field. For that reason, a Transport Layer
shall be present whenever the Application Layer is used in a message. The shortest Transport Layer (no
header) consists of this CI-field only. The CI-field of the Transport Layer declares the used application
protocol (like M-Bus Data, DLMS-Data or Alarm protocol), the origin of message (Command of Master or
Slave-Response) and the fixed header structure of the TPL header. Behind this CI-field, no other CI-field
follows.
The length of the APL is given by the message length reduced by the length of the other existing layers.
Table 2 — CI-field codes
TPL-
CI-field Direction Layer Higher layer protocol / Reference
Header
Reserved for DLMS-based
00 to 1F
APL None DLMS (see EN 13757-1)
h h
applications
NOTE 1 Introduce the presentation
b
Specific usage APL None
h
layer of Bibliographical Entry [16]
NOTE 1 Introduce the presentation
b
APL None
Specific usage
h
layer of Bibliographical Entry [16]
NOTE 1 Introduce the presentation
b
APL None
Specific usage
h
layer of Bibliographical Entry [16]
23 to 4F
Reserved
h h
Application reset or select to Application Selection;
APL None
h
device according to EN 13757-3:2025, Clause 7
Command to device M-Bus (not for wireless);
APL None
h
(full M-Bus frame) according to EN 13757-3:2025, Clause 6
Selection of device None Management, see 8.4
h
Application reset or select to Application Selection;
APL Long
h
device according to EN 13757-3:2025, Clause 7
Request of selected Application Selection;
APL None
h
application to device according to EN 13757-3:2025, Clause 7
Request of selected Application Selection;
APL Long
h
application to device according to EN 13757-3:2025, Clause 7
Request of selected Application Selection;
c
APL Short
h
application to device according to EN 13757-3:2025, Clause 7
TPL-
CI-field Direction Layer Higher layer protocol / Reference
Header
Application reset or select to Application Selection;
c
APL
Short
h
device according to EN 13757-3:2025, Clause 7
58 to 59
Reserved
h h
M-Bus;
Command to device
c
5A
APL Short
h
(full M-Bus frame)
according to EN 13757-3:2025, Clause 6
M-Bus;
Command to device
5B
APL Long
h
(full M-Bus frame)
according to EN 13757-3:2025, Clause 6
5C
Synchronize action APL None according to EN 13757-3:2025, Clause 12
h
5D
Reserved
h
b c
5E
Specific usage TPL Short NOTE 2 See Bibliographical Entry [8].
h
b
5F
TPL Long NOTE 2 See Bibliographical Entry [8].
Specific usage
h
DLMS/COSEM with OBIS-Identifier
Command to device APL Long (according to EN 13757-1 and EN 62056-
h
a
5–3)
DLMS/COSEM with OBIS-Identifier
c
Command to device APL (according to EN 13757-1 and EN 62056-
Short
h
a
5–3)
c
Time sync to device APL According to EN 13757-3:2025, Clause 8
Short
h
Reserved
h
a
Command to device APL Long
Reserved for OBIS-type value descriptors
h
c a
Command to device APL
Short Reserved for OBIS-type value descriptors
h
Response of selected Application Selection;
APL None
h
application from device according to EN 13757-3:2025, Clause 7
Response of selected Application Selection;
APL Short
h
application from device according to EN 13757-3:2025, Clause 7
Response of selected Application Selection;
APL Long
h
application from device according to EN 13757-3:2025, Clause 7
Response from device (M-Bus- M-Bus; according to EN 13757-3:2025,
APL None
h
Format frame) Clause 6 and Annex G
Response from device (M-Bus- M-Bus; according to EN 13757-3:2025,
6A
APL Short
h
Format frame) Clause 6 and Annex G
Response from device (M-Bus- M-Bus; according to EN 13757-3:2025,
6B
APL Long
h
Format frame) Clause 6 and Annex G
6C
Time sync to device APL Long According to EN 13757-3:2025, Clause 8
h
Deprecated (formerly Time
6D
APL Long
h
sync to device)
6E
Application error from device APL Short According to EN 13757-3:2025, Clause 10
h
6F
Application error from device APL Long According to EN 13757-3:2025, Clause 10
h
TPL-
CI-field Direction Layer Higher layer protocol / Reference
Header
Application error from device APL None According to EN 13757-3:2025, Clause 10
h
Alarm from device APL None According to EN 13757-3:2025, Clause 9
h
Response from device M-Bus; according to EN 13757-3:2025,
APL Long
h
(full M-Bus frame) Clause 6
Response from device (M-Bus- M-Bus; according to EN 13757-3:2025,
APL Long
h
Compact frame) Clause 6 and Annex G
Alarm from device APL Short According to EN 13757-3:2025, Clause 9
h
Alarm from device APL Long According to EN 13757-3:2025, Clause 9
h
76 to 77
Reserved
h h
Response from device M-Bus; according to EN 13757-3:2025,
APL None
h
(full M-Bus frame) Clause 6
Response from device (M-Bus- M-Bus; according to EN 13757-3:2025,
APL None
h
Compact frame) Clause 6 and Annex G
Response from device M-Bus; according to EN 13757-3:2025,
7A
APL Short
h
(full M-Bus frame) Clause 6
Response from device (M-Bus- M-Bus; according to EN 13757-3:2025,
7B
APL Short
h
Compact frame) Clause 6 and Annex G
DLMS/COSEM with OBIS-Identifier
7C
(according to EN 13757-1 and EN 62056-
Response from device APL Long
h
a
5–3)
DLMS/COSEM with OBIS-Identifier
7D (according to EN 13757-1 and EN 62056-
Response from device APL Short
h
a
5–3)
a
7E
Response from device APL Long Reserved for OBIS-type value descriptors
h
a
7F
Response from device APL Short Reserved for OBIS-type value descriptors
h
Transport Layer to device
TPL Long According to EN 13757-4
h
(without APL)
Network Layer data NWL n/a According to EN 13757-5
h
Network management data to
APL Long According to EN 13757-4 and EN 13757-5
h
device
Network management data to
APL None According to EN 13757-4 and EN 13757-5
h
device
Transport Layer to device (M-
TPL Long According to EN 13757-3:2025, Annex G
h
Bus-Compact frame expected)
Transport Layer to device (M-
TPL Long According to EN 13757-3:2025, Annex G
h
Bus-Format frame expected)
Reserved for Extended Link
ELL n/a According to EN 13757-4
h
Layer
Network management data
APL Long According to EN 13757-4, EN 13757-5
h
from device
TPL-
CI-field Direction Layer Higher layer protocol / Reference
Header
Network management data
APL Short According to EN 13757-4, EN 13757-5
h
from device
Network management data
APL None According to EN 13757-4, EN 13757-5
h
from device
Transport Layer from device
8A
TPL Short According to EN 13757-4
h
(without APL)
Transport Layer from device
8B
TPL Long According to EN 13757-4
h
(without APL)
8C to 8F
Extended Link Layer ELL n/a According to EN 13757-4
h h
Authentication and
AFL n/a According to Clause 6
h
Fragmentation Sublayer
Reserved
h
Network management data to
c
APL According to EN 13757-4 and EN 13757-5
Short
h
device
Transport Layer to device
c
TPL According to EN 13757-4
Short
h
(without APL)
Transport Layer to device (M-
c
TPL According to EN 13757-3:2025, Annex G
Short
h
Bus-Compact frame expected)
Transport Layer to device (M-
c
TPL Short According to EN 13757-3:2025, Annex G
h
Bus-Format frame expected)
96 to 97
Reserved According to EN 13757-4, EN 13757-5
h h
98 – 9D
Reserved
h h
b c
9E
TPL NOTE 2 See Bibliographical Entry [8].
Specific usage Short
h
b
9F
Specific usage TPL Long NOTE 2 See Bibliographical Entry [8].
h
A0 to B7
...
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