EN ISO 16484-5:2026
(Main)Building automation and control systems (BACS) - Part 5: Data communication protocol (ISO 16484-5:2026)
- Abstract
The purpose of this document is to define data communication services and protocols for computer equipment used for monitoring and control of HVAC&R and other building systems and to define, in addition, an abstract, object-oriented representation of information communicated between such equipment, thereby facilitating the application and use of digital control technology in buildings.
- Status
- Published
- Publication Date
- 25-Aug-2026
- Technical Committee
- CEN/TC 247 - Controls for mechanical building services
- Drafting Committee
- CEN/TC 247/WG 4 - Open System Data Transmission
- Current Stage
- 6060 - Definitive text made available (DAV) - Publishing
- Start Date
- 26-Aug-2026
- Completion Date
- 26-Aug-2026
EN ISO 16484-5:2026 is the CEN adoption of ISO 16484-5:2026 for Building automation and control systems (BACS), Part 5. It specifies the BACnet data communication protocol for equipment used to monitor and control HVAC&R and other building systems, and it defines the object-oriented information model those devices use to exchange data. Engineers, integrators, buyers, and quality teams use it to specify interoperable building control communications and device behavior.
What does EN ISO 16484-5:2026 specify?
EN ISO 16484-5:2026 defines the communication services, protocol behavior, and object model used by BACnet devices in building automation and control systems. Its scope covers encoded binary, analog, and alphanumeric data, plus schedules, alarms and events, files, and control logic.
The document is organized from general purpose and definitions through protocol layers, object types, services, procedures, encoding, conformance, and annexes. That structure matters in practice because it lets a reader move from network setup to device data modeling to interoperability and testing.
| Annex | What it covers |
|---|---|
| A | Protocol Implementation Conformance Statement (PICS) |
| B | Guide to specifying BACnet devices |
| E | Examples of BACnet application services |
| F | Examples of APDU encoding |
| G | Calculation of CRC |
| H | Combining BACnet networks with non-BACnet networks |
| I | Commandable properties with minimum on and off times |
| J | BACnet/IP |
| K | BACnet Interoperability Building Blocks (BIBBs) |
| N | Former BACnet/WS web services interface |
| U | BACnet/IPv6 |
| V | Migration from SOAP services |
| W | BACnet/WS RESTful web services interface |
| X | PICS declarations and object/property/datatype examples |
| Y | Abstract data model |
| Z | JSON data formats |
| AA | Time series data exchange file format and certificate authority requirements interchange file format |
| AB | BACnet Secure Connect |
| AC | Examples of authentication and authorization |
| AD | BACnet Energy Services Interface |
What are the key requirements of EN ISO 16484-5:2026?
EN ISO 16484-5:2026 sets out how BACnet devices communicate, how they are modeled as objects, and how different network technologies carry BACnet data. For implementation, the most important points are the protocol stack, message handling, data link mappings, and the standardized services and object properties.
Protocol architecture and addressing
EN ISO 16484-5:2026 uses a four-layer collapsed architecture aligned to the physical, data link, network, and application layers of the OSI model. Clause 4 also describes BACnet network topology as flexible rather than fixed, with devices attached to local area networks or serial links and interconnected by BACnet routers.
This matters because system designers have to choose the right LAN type, router arrangement, and addressing scheme for the site. Clause 6 says a device is located by a network number and a MAC address, which is the basis for routing between BACnet networks.
Application layer behavior
EN ISO 16484-5:2026 defines application-layer segmentation, transmission rules, state machines, time-sequence diagrams, and service conventions in Clauses 5.2 to 5.6. Only Confirmed-Request and ComplexACK messages may be segmented, and segmentation is optional.
In practice, this is what controls large messages, retry behavior, and timing. The client and server state machines, together with the APDU_Timeout-related behavior in Clause 5.3, tell implementers how to handle acknowledgments, errors, rejects, aborts, duplicates, and incomplete transactions.
Network layer functions
EN ISO 16484-5:2026 gives the BACnet network layer unacknowledged connectionless transfer services and the message formats that support routing, broadcast, multicast, and network management. Clause 6 also defines router procedures, including BACnet routers and point-to-point half-routers.
That matters when devices sit on different BACnet networks or different media. The document also sets rules for network-layer messages such as router discovery, routing table updates, congestion control, and establishment or disconnection of network connections.
Data link and physical layer mappings
EN ISO 16484-5:2026 maps BACnet onto several data link and physical technologies, including Ethernet, ARCNET, Multidrop Serial Bus/Token Passing (MS/TP), Point-to-Point (PTP), LonTalk, BACnet/IP, BACnet/IPv6, ZigBee, and BACnet Secure Connect. Clauses 7 to 11 describe the service mappings, frame formats, and media rules for those transports.
For implementers, this is where cable type, frame structure, priority handling, and error detection become concrete. MS/TP uses token passing on EIA-485, Ethernet and ARCNET use LLC Class I, PTP uses alternating-bit acknowledgement, and LonTalk maps BACnet to the LonTalk application layer.
Object model and standard services
EN ISO 16484-5:2026 models each device as a collection of objects, and Clause 12 defines common object rules and many standard object types. Every object has an Object_Identifier, and each object in a device has a unique value for that property.
This is central to day-to-day use because application services read and write object properties rather than device internals. The standard includes object types for analog and binary inputs and outputs, schedules, trend logs, access control, lighting, elevators, audit reporting, and color-related functions, so the same protocol can cover many building subsystems.
Conformance, security, and extensions
EN ISO 16484-5:2026 includes alarm and event services, file access, object access, remote device management, authentication and authorization, error handling, and BACnet procedures such as backup and restore, command prioritization, audit logging, discovery, and certificate replacement. Annex A provides the PICS structure, and Annex K sets out BACnet Interoperability Building Blocks (BIBBs).
This matters for procurement and testing because it gives a common way to declare device capabilities and check interoperability. Clause 17 and Annex AC also show that authentication and authorization are part of the document’s security model, while Clause 23 defines how vendor-proprietary information may be added without breaking the standardized model.
What terms does EN ISO 16484-5:2026 define?
- Application Protocol Data Unit (APDU) - The application-layer packet exchanged between BACnet devices, including confirmed and unconfirmed service messages.
- BACnet router - A device that interconnects BACnet networks and relays network-layer traffic between them.
- BACnet Secure Connect (BACnet/SC) - The BACnet secure-connect profile covered in Annex AB for secure network connections and node operation.
- Multidrop Serial Bus/Token Passing (MS/TP) - A BACnet data link protocol that uses token passing over an EIA-485 bus.
- Object_Identifier - The property that identifies every BACnet object by object type and object instance.
- Protocol Implementation Conformance Statement (PICS) - The statement format in Annex A used to declare which BACnet capabilities a device implements.
- BACnet/IPv6 (B/IPv6) - The BACnet IPv6 profile covered in Annex U for BACnet communication over IPv6-based transport.
Who uses EN ISO 16484-5:2026?
EN ISO 16484-5:2026 is used by BACS manufacturers, system integrators, and software developers who implement BACnet devices, controllers, gateways, and supervisory systems. It is also used by commissioning engineers and test labs when they need to verify object behavior, services, and transport compatibility.
Facility owners, specifiers, buyers, and quality managers use it to define what a device must be able to communicate, how interoperability is declared, and which BACnet options a project should accept. It is relevant across HVAC&R, lighting, access control, lifts, energy management, and other building systems that exchange structured control data.
What changed in EN ISO 16484-5:2026 from the previous edition?
EN ISO 16484-5:2026 supersedes EN ISO 16484-5:2022.
Which standards are used with EN ISO 16484-5:2026?
- ISO 7498 - Provides the OSI basic reference model used to explain BACnet’s layered architecture.
- ISO TR 8509 - Provides the service conventions used to describe application-layer service primitives.
- ISO 8802-2 - Supplies the LLC service model used in the Ethernet, ARCNET, and LonTalk mappings.
- ISO/IEC 8802-3 - Supplies the Ethernet LAN transport described in Clause 7.
- ATA 878.1 - Supplies the ARCNET LAN transport described in Clause 8.
- EIA-485 - Supplies the physical-layer basis for MS/TP in Clause 9.
- ISO/IEC 14908.1 - Supplies the LonTalk transport referenced in Clause 11.
- EIA/CEA-709.1-B-2002 - The LonTalk control network protocol specification referenced for BACnet over LonTalk.
What does the EN ISO 16484-5:2026 document contain?
EN ISO 16484-5:2026 contains protocol architecture descriptions, service models, state machines, message formats, and routing procedures that are used to implement and test BACnet communications. Clauses 5 and 6 include transmission rules, network-layer PDUs, router messages, and point-to-point procedures; Clauses 7 to 11 give the transport mappings for Ethernet, ARCNET, MS/TP, PTP, and LonTalk.
The document also contains large tables of object types and properties in Clause 12, together with the alarm, event, file access, object access, and device-management services in Clauses 13 to 19. Annexes provide conformance statements, worked examples of services and APDU encoding, CRC calculations, gateway guidance, BACnet/IP, BACnet/IPv6, BACnet Secure Connect, JSON data formats, abstract data modeling, and BACnet Energy Services Interface material.
Relations
- Effective Date
- 21-May-2025
- Effective Date
- 02-Sep-2026
- Effective Date
- 02-Sep-2026
- Effective Date
- 02-Sep-2026
- Consolidated By
ISO 16484-5:2026 - Building automation and control systems (BACS) — Part 5: Data communication protocol - Effective Date
- 12-Feb-2026
Frequently Asked Questions
EN ISO 16484-5:2026 is a standard published by the European Committee for Standardization (CEN). Its full title is "Building automation and control systems (BACS) - Part 5: Data communication protocol (ISO 16484-5:2026)". This standard covers: The purpose of this document is to define data communication services and protocols for computer equipment used for monitoring and control of HVAC&R and other building systems and to define, in addition, an abstract, object-oriented representation of information communicated between such equipment, thereby facilitating the application and use of digital control technology in buildings.
The purpose of this document is to define data communication services and protocols for computer equipment used for monitoring and control of HVAC&R and other building systems and to define, in addition, an abstract, object-oriented representation of information communicated between such equipment, thereby facilitating the application and use of digital control technology in buildings.
EN ISO 16484-5:2026 has the following relationships with other standards: It is inter standard links to EN ISO 16484-5:2022, EN IEC 60730-1:2024, EN ISO 16484-3:2005, CEN/TR 18081:2024, ISO 16484-5:2026. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
EN ISO 16484-5:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-oktober-2026
Nadomešča:
SIST EN ISO 16484-5:2022
Sistemi za avtomatizacijo in regulacijo stavb - 5. del: Protokol za izmenjavo
podatkov (ISO 16484-5:2026)
Building automation and control systems (BACS) - Part 5: Data communication protocol
(ISO 16484-5:2026)
Systeme der Gebäudeautomation - Teil 5: Datenkommunikationsprotokoll (ISO 16484-
5:2026)
Systèmes de contrôle et d'automatisation des bâtiments (BACS) - Partie 5: Protocole de
communication de données (ISO 16484-5:2026)
Ta slovenski standard je istoveten z: EN ISO 16484-5:2026
ICS:
35.240.67 Uporabniške rešitve IT v IT applications in building
gradbeništvu and construction industry
97.120 Avtomatske krmilne naprave Automatic controls for
za dom household use
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 16484-5
EUROPEAN STANDARD
NORME EUROPÉENNE
August 2026
EUROPÄISCHE NORM
ICS Supersedes EN ISO 16484-5:2022
English Version
Building automation and control systems (BACS) - Part 5:
Data communication protocol (ISO 16484-5:2026)
Systèmes d'automatisation et de gestion technique du Systeme der Gebäudeautomation - Teil 5:
bâtiment (BACS) - Partie 5: Protocole de Datenkommunikationsprotokoll (ISO 16484-5:2026)
communication de données (ISO 16484-5:2026)
This European Standard was approved by CEN on 26 July 2026.
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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 16484-5:2026 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 16484-5:2026) has been prepared by Technical Committee ISO/TC 205
"Building environment design" in collaboration with Technical Committee CEN/TC 247 “Building
Automation, Controls and Building Management” the secretariat of which is held by SNV.
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 February 2027, and conflicting national standards
shall be withdrawn at the latest by February 2027.
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 ISO 16484-5:2022.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations 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.
Endorsement notice
The text of ISO 16484-5:2026 has been approved by CEN as EN ISO 16484-5:2026 without any
modification.
International
Standard
ISO 16484-5
Eighth edition
Building automation and control
2026-08
systems (BACS) —
Part 5:
Data communication protocol
Systèmes d'automatisation et de gestion technique du bâtiment
(BACS) —
Partie 5: Protocole de communication de données
Reference number
ISO 16484-5:2026(en) © ISO 2026
ISO 16484-5:2026(en)
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 16484-5:2026(en)
CONTENTS
Foreword . xi
FOREWORD . xii
1 PURPOSE . 1
2 SCOPE . 1
3 DEFINITIONS . 1
3.1 Terms Adopted from International Standards . 1
3.2 Terms Defined for this Standard . 2
3.3 Abbreviations and Acronyms Used in this Standard . 8
4 BACnet PROTOCOL ARCHITECTURE . 12
4.1 The BACnet Collapsed Architecture . 13
4.2 BACnet Network Topology . 15
4.3 Security . 16
5 THE APPLICATION LAYER . 17
5.1 The Application Layer Model . 17
5.2 Segmentation of BACnet Messages . 23
5.3 Transmission of BACnet APDUs . 24
5.4 Application Protocol State Machines . 28
5.5 Application Protocol Time Sequence Diagrams . 46
5.6 Application Layer Service Conventions . 55
6 THE NETWORK LAYER . 57
6.1 Network Layer Service Specification . 57
6.2 Network Layer PDU Structure . 59
6.3 Messages for Multiple Recipients . 65
6.4 Network Layer Protocol Messages . 65
6.5 Network Layer Procedures . 69
6.6 BACnet Routers . 71
6.7 Point-To-Point Half-Routers . 76
7 DATA LINK/PHYSICAL LAYERS: Ethernet (ISO 8802-3) LAN . 81
7.1 The Use of ISO 8802-2 Logical Link Control (LLC) . 81
7.2 Parameters Required by the LLC Primitives . 81
7.3 Parameters Required by the MAC Primitives . 81
7.4 Physical Media . 81
8 DATA LINK/PHYSICAL LAYERS: ARCNET (ATA 878.1) LAN . 82
8.1 The Use of ISO 8802-2 Logical Link Control (LLC) . 82
8.2 Parameters Required by the LLC Primitives . 82
8.3 Mapping the LLC Services to the ARCNET MAC Layer . 82
8.4 Parameters Required by the MAC Primitives . 82
8.5 Physical Media . 82
9 DATA LINK/PHYSICAL LAYERS: MULTIDROP SERIAL BUS/TOKEN PASSING (MS/TP) LAN . 84
9.1 Service Specification . 84
9.2 Physical Layer . 86
9.3 MS/TP Frame Format . 96
9.4 Overview of the MS/TP Network . 98
9.5 MS/TP Medium Access Control . 99
9.6 Cyclic Redundancy Check (CRC) . 120
9.7 Interfacing MS/TP LANs with Other BACnet LANs . 121
9.8 Responding BACnet User Processing of Messages from MS/TP . 121
9.9 Repeaters . 122
9.10 COBS (Consistent Overhead Byte Stuffing) Encoding . 123
9.11 Documenting MS/TP Node Design Choices. 127
10 DATA LINK/PHYSICAL LAYERS: POINT-TO-POINT (PTP) . 128
10.1 Overview . 128
10.2 Service Specification . 128
10.3 Point-to-Point Frame Format . 133
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ISO 16484-5:2026(en)
10.4 PTP Medium Access Control Protocol . 135
11 DATA LINK/PHYSICAL LAYERS: LonTalk (ISO/IEC 14908.1) LAN . 157
11.1 The Use of ISO 8802-2 Logical Link Control (LLC) . 157
11.2 Parameters Required by the LLC Primitives . 157
11.3 Mapping the LLC Services to the LonTalk Application Layer . 157
11.4 Parameters Required by the Application Layer Primitives . 157
11.5 Physical Media . 158
12 MODELING CONTROL DEVICES AS A COLLECTION OF OBJECTS . 160
12.1 Object Characteristics and Requirements . 160
12.2 Analog Input Object Type . 167
12.3 Analog Output Object Type . 174
12.4 Analog Value Object Type . 182
12.5 Averaging Object Type . 190
12.6 Binary Input Object Type . 194
12.7 Binary Output Object Type . 201
12.8 Binary Value Object Type . 210
12.9 Calendar Object Type . 218
12.10 Command Object Type . 221
12.11 Device Object Type . 228
12.12 Event Enrollment Object Type . 244
12.13 File Object Type . 253
12.14 Group Object Type . 257
12.15 Life Safety Point Object Type . 260
12.16 Life Safety Zone Object Type . 268
12.17 Loop Object Type . 276
12.18 Multi-state Input Object Type . 286
12.19 Multi-state Output Object Type . 292
12.20 Multi-state Value Object Type . 299
12.21 Notification Class Object Type . 307
12.22 Program Object Type . 313
12.23 Pulse Converter Object Type . 320
12.24 Schedule Object Type . 328
12.25 Trend Log Object Type . 336
12.26 Access Door Object Type . 347
12.27 Event Log Object Type . 357
12.28 Load Control Object Type . 365
12.29 Structured View Object Type . 376
12.30 Trend Log Multiple Object Type . 381
12.31 Access Point Object Type . 391
12.32 Access Zone Object Type . 409
12.33 Access User Object Type . 418
12.34 Access Rights Object Type . 422
12.35 Access Credential Object Type . 429
12.36 Credential Data Input Object Type . 439
12.37 CharacterString Value Object Type . 446
12.38 DateTime Value Object Type . 453
12.39 Large Analog Value Object Type . 459
12.40 BitString Value Object Type . 467
12.41 OctetString Value Object Type . 474
12.42 Time Value Object Type . 479
12.43 Integer Value Object Type . 485
12.44 Positive Integer Value Object Type . 493
12.45 Date Value Object Type . 501
12.46 DateTime Pattern Value Object Type . 507
12.47 Time Pattern Value Object Type . 513
12.48 Date Pattern Value Object Type . 519
12.49 Deleted Clause . 525
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ISO 16484-5:2026(en)
12.50 Global Group Object Type . 526
12.51 Notification Forwarder Object Type . 534
12.52 Alert Enrollment Object Type . 542
12.53 Channel Object Type . 546
12.54 Lighting Output Object Type . 557
12.55 Binary Lighting Output Object Type . 575
12.56 Network Port Object Type . 587
12.57 Timer Object Type . 629
12.58 Elevator Group Object Type . 642
12.59 Lift Object Type. 646
12.60 Escalator Object Type . 659
12.61 Accumulator Object Type . 667
12.62 Staging Object Type . 677
12.63 Audit Reporter Object Type . 688
12.64 Audit Log Object Type . 694
12.65 Color Object Type . 701
12.66 Color Temperature Object Type . 707
13 ALARM AND EVENT SERVICES . 714
13.1 Change of Value Reporting . 714
13.2 Event Reporting . 719
13.3 Event Algorithms . 732
13.4 Fault Algorithms . 764
13.5 AcknowledgeAlarm Service . 772
13.6 ConfirmedCOVNotification Service . 774
13.7 UnconfirmedCOVNotification Service . 776
13.8 ConfirmedEventNotification Service . 777
13.9 UnconfirmedEventNotification Service . 780
13.10 GetAlarmSummary Service . 783
13.11 GetEnrollmentSummary Service . 785
13.12 GetEventInformation Service . 788
13.13 LifeSafetyOperation Service . 791
13.14 SubscribeCOV Service . 793
13.15 SubscribeCOVProperty Service . 796
13.16 SubscribeCOVPropertyMultiple Service . 799
13.17 ConfirmedCOVNotificationMultiple Service . 805
13.18 UnconfirmedCOVNotificationMultiple Service . 808
13.19 AuditLogQuery . 810
13.20 ConfirmedAuditNotification . 814
13.21 UnconfirmedAuditNotification . 815
14 FILE ACCESS SERVICES . 816
14.1 AtomicReadFile Service . 816
14.2 AtomicWriteFile Service . 819
15 OBJECT ACCESS SERVICES . 822
15.1 AddListElement Service . 822
15.2 RemoveListElement Service . 825
15.3 CreateObject Service . 827
15.4 DeleteObject Service . 830
15.5 ReadProperty Service . 831
15.6 Deleted Clause . 833
15.7 ReadPropertyMultiple Service . 834
15.8 ReadRange Service . 837
15.9 WriteProperty Service . 845
15.10 WritePropertyMultiple Service . 848
15.11 WriteGroup Service . 851
16 REMOTE DEVICE MANAGEMENT SERVICES . 853
16.1 DeviceCommunicationControl Service . 853
16.2 ConfirmedPrivateTransfer Service . 855
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ISO 16484-5:2026(en)
16.3 UnconfirmedPrivateTransfer Service . 857
16.4 ReinitializeDevice Service . 858
16.5 ConfirmedTextMessage Service . 860
16.6 UnconfirmedTextMessage Service . 862
16.7 TimeSynchronization Service . 863
16.8 UTCTimeSynchronization Service . 864
16.9 Who-Has and I-Have Services . 865
16.10 Who-Is and I-Am Services . 867
16.11 Who-Am-I and You-Are Services . 869
17 AUTHENTICATION AND AUTHORIZATION SERVICES . 872
17.1 Overview . 872
17.2 Trust of Intermediaries . 873
17.3 Authentication . 874
17.4 Authorization . 876
17.5 Conformance Requirements . 882
17.6 AuthRequest Service . 883
18 ERROR, REJECT, and ABORT CODES . 887
18.1 Error Class - DEVICE . 887
18.2 Error Class - OBJECT . 887
18.3 Error Class - PROPERTY . 888
18.4 Error Class - RESOURCES . 890
18.5 Error Class - SECURITY. 890
18.6 Error Class - SERVICES . 892
18.7 Error Class - COMMUNICATION . 893
18.8 Error Class - VT . 898
18.9 Reject Reason . 898
18.10 Abort Reason . 899
18.11 Confirmed Service Common Errors . 900
19 BACnet PROCEDURES . 901
19.1 Backup and Restore . 901
19.2 Command Prioritization . 906
19.3 Device Restart Procedure . 911
19.4 Determining Maximum Conveyable APDU . 912
19.5 Value Source Mechanism . 914
19.6 Audit Logging . 916
19.7 Unconfigured Device Discovery and Address Assignment . 927
19.8 Replacing Certificates in a BACnet/SC Network . 928
19.9 Device Address Proxying . 930
20 ENCODING BACnet PROTOCOL DATA UNITS . 934
20.1 Encoding the Fixed Part of BACnet APDUs . 935
20.2 Encoding the Variable Part of BACnet APDUs . 947
21 FORMAL DESCRIPTION OF APPLICATION PROTOCOL DATA UNITS . 963
21.1 APDU Definitions. 963
21.2 Confirmed Service Productions . 965
21.3 Unconfirmed Service Productions . 976
21.4 Error Productions . 980
21.5 Application Types . 992
21.6 Base Types . 994
22 CONFORMANCE AND INTEROPERABILITY . 1082
22.1 Conformance to BACnet. 1082
22.2 BACnet Interoperability . 1083
23 EXTENDING BACnet TO ACCOMMODATE VENDOR PROPRIETARY INFORMATION . 1085
23.1 Extending Enumeration Values . 1085
23.2 Using the PrivateTransfer Services to Invoke Non-Standardized Services . 1086
23.3 Adding Proprietary Properties to a Standardized Object . 1086
23.4 Adding Proprietary Object Types to BACnet . 1087
23.5 Restrictions on Extending BACnet . 1087
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ISO 16484-5:2026(en)
24 DELETED CLAUSE . 1088
25 REFERENCES . 1089
ANNEX A - PROTOCOL IMPLEMENTATION CONFORMANCE STATEMENT (NORMATIVE) . 1094
ANNEX B - GUIDE TO SPECIFYING BACnet DEVICES (INFORMATIVE) . 1098
ANNEX C - Removed .
...