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BACnet Logo Official Web Site of ASHRAE SSPC 135
INTERPRETATIONS
 
Occasionally the SSPC receives requests for official interpretations of Standards 135 and 135.1. An "Interpretation" is "The written explanation of the meaning of specific provisions of a standard or guideline, as determined by the IC [Interpretations Committee] or the PC [Project Committee, i.e., SSPC 135] in response to an inquiry." The following PDF files contain all such interpretations to date.

To jump to the interpretations for a particular consolidated version of the standard, click below:

135-2001
135-2004
135-2008
135-2010
135-2012
135-2016

Interpretations of 135-2001

Interpretation 135-2001-1 - June 26, 2004 (Refers to the requirements presented in ANSI/ASHRAE Addendum b to ANSI/ASHRAE Standard 135-2001, Section 15.8 ReadRange Service.)

Interpretations of 135-2004

Interpretation 135-2004-1 - June 26, 2004 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 16.1 DeviceCommunicationControl Service, specifically Section 16.1.2 (page 326), relating to the canceling of DeviceCommunicationControl disabling of communication via a ReinitializeDevice request.)

Interpretation 135-2004-2 - June 26, 2004 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 13.11 GetEnrollmentSummary Service, specifically Section 13.11.1.2.1.4 (page 283), relating to the priority returned in a GetEnrollmentSummary response.)

Interpretation 135-2004-3 - June 26, 2004 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 12.25.5, Log_Enable, and Section 12.25.12, Stop_When_Full.)

Interpretation 135-2004-4 - June 26, 2004 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Sections 12.25.14, Log_Buffer, 12.25, and 15.7.2, Service Procedure.)

Interpretation 135-2004-5 - June 26, 2004 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 12.25.5, Log_Enable, and Section 12.25.12, Stop_When_Full.)

Interpretation 135-2004-6 - February 5, 2005 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 12.24.8, Exception_Schedule.)

Interpretation 135-2004-7 - February 5, 2005 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Sections K.5.15 and K.5.16.)

Interpretation 135-2004-8 - June 25, 2005 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004 in the following sections and tables relating to FLOATING_LIMIT and OUT_OF_RANGE transitions: Sections 12.2.19-12.2.21, Sections 12.3.20-12.3.22, Sections 12.4.16-12.4.18, Section 12.17.32, Sections 12.23.22-12.23.24, Section 13.3.5, Section 13.3.6, Table 13.2.)

Interpretation 135-2004-9 - June 25, 2005 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Sections 12.1-12.4, 12.6-12.8, 12.15-12.20, 12.23, 12.25, and the corresponding tables in these sections, relating to intrinsic reporting.)

Interpretation 135-2004-10 - June 25, 2005 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 6.6.1, Routing Tables, and Section 6.6.3.6, Router- Busy-To-Network.)

Interpretation 135-2004-11 - June 25, 2005 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 12.25.14, Log_Buffer, and Section 15.7.3.1.2, List of Property References.)

Interpretation 135-2004-12 - June 25, 2005 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 6.4.4, Reject-Message-To-Network, and Section 6.6.3.5, Reject-Message-To-Network.)

Interpretation 135-2004-13 - June 25, 2005 (Refers refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Sections 12.1.10, 12.2.10, 12.3.10, 12.4.9, 12.6.10, 12.7.10, 12.8.9, 12.15.11, 12.16.11, 12.17.9, 12.18.10, 12.19.10, 12.20.9, 12.23.10, relating to the Reliability and Out_Of_Service properties.)

Interpretation 135-2004-14 - September 28, 2005 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 6.3.2, relating to Network Layer routing.)

Interpretation 135-2004-15 - September 28, 2005 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Annex J - BACnet/IP, specifically Section J.2.6.1, Register-Foreign-Device: Format.)

Interpretation 135-2004-16 - June 24, 2006 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Sections 12.1.8, 12.2.8, 12.3.8, 12.4.7, 12.6.8, 12.7.8, 12.8.7, 12.17.7, 12.18.8, 12.20.7, and 12.23.8 related to Event_State and Relibility properties.)

Interpretation 135-2004-17 - April 24, 2006 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 12.25.14, related to Log_Buffer.)

Interpretation 135-2004-18 - January 21, 2006 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 12.25.9, related to Log_Interval.)

Interpretation 135-2004-18 - January 21, 2006 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 12.25.9, related to Log_Interval.)

Interpretation 135-2004-19 - January 27, 2007 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Sections.15.9.1.1.5, 15.10.3.2.4 and 19.2.1, related to writing properties with an out-of-range priority.)

Interpretation 135-2004-20 - January 27, 2007 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Sections 5.4, 5.4.1, 5.4.5.1, 5.4.5.3, and 12.11.27 related to the Device Object and the APDU_Timeout property.)

Interpretation 135-2004-21 - January 27, 2007 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 12.24.4, 12.24.7 and 12.24.8 regarding when the Present_Value of an object is evaluated within a selected Weekly_Schedule or Exception_Schedule.)

Interpretation 135-2004-22 - April 25, 2007 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Sections 6.5.3 and 9.5.6.4 regarding the methods for establishing the address of a BACnet router for a particular DNET.)

Interpretation 135-2004-23 - June 21, 2008 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 13.2 relating to intrinsic reporting.)

Interpretation 135-2004-24 - June 21, 2008 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Sections 19.2, 21 and 23.3, and Addendum f to ANSI/ASHRAE Standard 135-2004 regarding ENUMERATED values in BACnetPriorityValue.)

Interpretation 135-2004-25 - June 21, 2008 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Sections 13.2 and 13.3 relating to fault event reporting.)

Interpretation 135-2004-26 - September 17, 2008 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 13.11.1.1.5 regarding Priority Filter.)

Interpretation 135-2004-27 - September 17, 2008 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 21 relating to BACnetEventParameters 'buffer-ready' choice.)

Interpretation 135-2004-28 - September 17, 2008 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Sections 15.10.1.3.1 and 18.8.4 relating to WritePropertyMultiple with incorrect datatype.)

Interpretation 135-2004-29 - January 24, 2009 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2004, Section 19.1.3.2, relating to creating configuration File objects in the restore process.)

Interpretations of 135-2008

Interpretation 135-2008-1 - June 20, 2009 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2008, Sections 12.19.10 and 12.20.10, relating to Shrinking Number_of_States in Commandable Multi-state objects.)

Interpretation 135-2008-2 - June 20, 2009 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2008, Section 12.24.4, related to the calculation of the Present_Value property of a Schedule object.)

Interpretation 135-2008-3 - January 23, 2010 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2008, Section 12, relating to the data type of the number of elements of an array when accessing an array property with array index 0.)

Interpretation 135-2008-4 - January 23, 2010 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2008, Section 12.13.7, File Object Modification_Date property value.)

Interpretation 135-2008-5 - May 28, 2010 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2008 relating to Date and Time.)

Interpretation 135-2008-6 - October 28, 2010 (Refers to the change of requirements presented in ANSI/ASHRAE Addendum l to ANSI/ASHRAE Standard 135-2008, Section 1 and ANSI/ASHRAE Addendum v to ANSI/ASHRAE Standard 135-2008, Section 3, relating to the support of the BIBB NM-CE-A in the device profile B-AWS.)

Interpretation 135-2008-7 - October 28, 2010 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2008, Clauses 5.4 and 5.4.5.3, relating to the CannotSendSegmentedComplexACK for the AWAIT_RESPONSE.)

Interpretation 135-2008-8 - October 28, 2010 (Refers to the requirements presented in Addendum g to ANSI/ASHRAE Standard 135-2008, Section 24.5 and Figure 24-2 (page 32), relating to securing proprietary network messages.)

Interpretation 135-2008-9 - October 28, 2010 (Refers to the requirements presented in Addendum g to ANSI/ASHRAE Standard 135-2008, Sections 12.X.15 and 24.16.2, relating to the Do_Not_Hide property of the Network Security object.)

Interpretation 135-2008-10 - October 28, 2010 (Refers to the requirements presented in Addendum g to ANSI/ASHRAE Standard 135-2008, Section 24.16.1, relating to APDU and NPDU sizes.)

Interpretation 135-2008-11 - October 28, 2010 (Refers to the requirements presented in Addendum p to ANSI/ASHRAE Standard 135-2008, Section 13.3.X, relating to the CHANGE_OF_STATUS_FLAGS Algorithm.)

Interpretation 135-2008-12 - October 28, 2010 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2008, Sections 12.1 and 12.1.11, relating to Accumulator object's Scale property.)

Interpretation 135-2008-13 - January 29, 2011 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2008, Clauses 6.4.7 and 6.4.8 (pages 55 and 56), relating Initialize-Routing-Table and Initialize-Routing-Table-Ack.)

Interpretation 135-2008-14 - January 29, 2011 (Refers to the requirements presented in Addendum g to ANSI/ASHRAE Standard 135-2008, Clause 24.2.11 (page 13), relating to Authentication Data length encoding.)

Interpretation 135-2008-15 - January 29, 2011 (Refers to the requirements presented in Addendum g to ANSI/ASHRAE Standard 135-2008, Clauses 24.2.3 and 24.12.1 (pages 11 and 40), relating to Selecting General-Network-Access key for encryption when another key is used for signing.)

Interpretation 135-2008-16 - January 29, 2011 (Refers to the requirements presented in Addendum g to ANSI/ASHRAE Standard 135-2008, Clause 24.16.2 and Tables 24-8, 24-18, 24-22 and 24-24 (pages 47, 19, 22-23, 26-27, 28-29), relating to order of error checking in key messages.)

Interpretation 135-2008-17 - January 29, 2011 (Refers to the requirements presented in Addendum g to ANSI/ASHRAE Standard 135-2008, Clauses 24.15.2.1 (page 45), relating to methods for discovering time.)

Interpretation 135-2008-18 - January 29, 2011 (Refers to the requirements presented in Addendum g to ANSI/ASHRAE Standard 135-2008, Clauses 24.2.8, 24.2.9, 24.3.7, 24.12.1, S.1 (pages 12, 29, 39, 98), relating to Security Applied to Request-Master-Key message.)

Interpretation 135-2008-19 - January 29, 2011 (Refers to the requirements presented in Addendum g to ANSI/ASHRAE Standard 135-2008, Clause 24.3.3.3 and Table 24.11 (page 20), relating to What it means for a device to "know a key".)

Interpretation 135-2008-20 - May 25, 2011 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2008, Clauses J.2 (page 617), relating to BACnet Broadcast Management Device (BBMD) and BACnet Virtual Link Layer (BVLL) Services.)

Interpretation 135-2008-21 - May 25, 2011 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2008, Clauses 12.25 (pages 259 and 281), relating to Timestamping of Trend Log records.)

Interpretations of 135-2010

Interpretation 135-2010-1 - May 25, 2011 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2010, Clause 12.24, relating to Schedule Object Type.)

Interpretation 135-2010-2 - October 27, 2011 (Refers to the requirements presented in ANSI/ASHRAE 135-2010 clauses 12.25.5 (Trend Log Object Type, Enable property) and 12.25.14 (Trend Log Object Type, Log_Buffer property). This interpretation request also applies to the corresponding property clauses of the Event Log Object Type (12.27.8, 12.27.13) and the Trend Log Multiple Object Type (12.30.8, 12.30.19).)

Interpretation 135-2010-3 - October 27, 2011 (Refers to the requirements presented in ANSI/ASHRAE 135-2010, Clause 12.11.50 (Device Object Type, Interval_Offset).)

Interpretation 135-2010-4 - July 16, 2012 (Refers to the requirements presented in ANSI/ASHRAE 135-2010, Clauses 5.2.1.2, 6, 6.4.4 and 6.6.3.5, as well as Table 6.1, relating to router requirements.)

Interpretation 135-2010-5 - July 16, 2012 (Refers to the requirements presented in ANSI/ASHRAE 135-2010, Clauses 12.25.9 and K.4.3, relating to T-VMT-E-B BIBB.)

Interpretation 135-2010-6 - June 13, 2012 (Refers to the requirements presented in ANSI/ASHRAE 135-2010, Clause 15.7.2, relating to the special property OPTIONAL.)

Interpretation 135-2010-7 - June 13, 2012 (Refers to standard ANSI/ASHRAE 135-2010, Clause 13.1, "Change of Value Reporting" on page 412, Table 13-1 on page 413, and Table 13-1a on page 414.)

Interpretation 135-2010-8 - November 7, 2012 (Refers to the requirements presented in ANSI/ASHRAE 135-2010, Clause 12.24.4 and 12.24.6, relating to the behavior of the property.)

Interpretation 135-2010-9 - November 7, 2012 (Refers to the requirements presented in ANSI/ASHRAE 135-2010, Clauses 15.1.1.4.1.2, 15.1.1.4.2.2, 15.1.1.4.3.2, and 15.8.2, relating to the content of ReadRange-ACK when MORE_ITEMS is true, and the Count in the ReadRange-Request was negative.)

Interpretation 135-2010-10 - November 7, 2012 (Refers to the requirements presented in ANSI/ASHRAE 135-2010, Clauses 12.25 Preamble and 12.27 Preamble and 12.30 Preamble, relating to the behavior of the property Total_Record_Count of logging objects.)

Interpretation 135-2010-11 - November 7, 2012 (Refers to standard ANSI/ASHRAE 135-2010, Clause 12.11.19, "Segmentation_Supported", and Clause 12.11.20, "Max_Segments_Accepted", both on page 199.)

Interpretation 135-2010-12 - January 26, 2013 (Refers to ANSI/ASHRAE Standard 135-2010, Clause 12, regarding the Object_Identifier property and the instance number 4194303.)

Interpretation 135-2010-13 - January 26, 2013 (Refers to the requirements presented in ANSI/ASHRAE 135-2010af-31, Clause 12.X, relating to the behavior of the AckRequired Boolean in ConfirmedEventNotification and UnconfirmedEventNotification requests.)

Interpretation 135-2010-14 - May 9, 2013 (Refers to ANSI/ASHRAE Standard 135-2010, Clauses 12.4.9, 12.8.9 and 12.20.9, regarding the Out_Of_Service property.)

Interpretations of 135-2012

Interpretation 135-2012-1 - May 9, 2013 (Refers to the requirements presented in ANSI/ASHRAE 135-2012, Clause 12.25.14, relating to recording time-change events in trendlog logbuffer.)

Interpretation 135-2012-2 - June 22, 2013 (Refers to ANSI/ASHRAE Standard 135-2012, Clause 19, regarding the Command Prioritization.)

Interpretation 135-2012-3 - June 22, 2013 (Refers to the requirements presented in ANSI/ASHRAE 135-2012, Clause K.5.23, relating to BBIB Device Management-Object Creation and Deletion-A (DM-OCD-A).)

Interpretation 135-2012-4 - June 22, 2013 (Refers to the requirements presented in ANSI/ASHRAE 135-2012, Clause 12.25.10, relating to details on client behavior for retrieving external property values by COV or polling.)

Interpretation 135-2012-5 - June 22, 2013 (Refers to ANSI/ASHRAE Standard 135-2012, Clauses 12.4.9, 12.8.9 and 12.20.9, regarding the Out_Of_Service property.)

Interpretation 135-2012-6 - November 6, 2013 (Refers to the requirements presented in ANSI/ASHRAE 135-2012, Clause 12.9.6, relating to the behavior of the Present_Value in a Calendar when the Date_List contains a specific day-of-week, and any of the special third octet values.)

Interpretation 135-2012-7 - November 6, 2013 (Refers to the requirements presented in ANSI/ASHRAE 135-2012, Clause 15.10.1.3 and 15.10.2, relating to error handling of WritePropertyMultiple Service.)

Interpretation 135-2012-8 - November 6, 2013 (Refers to the requirements presented in ANSI/ASHRAE 135-2012, Clauses 12.18.10 and 13.4.5, relating to the correct value of reliability when OutOfService.)

Interpretation 135-2012-9 - November 6, 2013 (Refers to the requirements presented in ANSI/ASHRAE 135-2012, Clause 12, relating to the execution of alarming related messages containing timestamps with wildcards.)

Interpretation 135-2012-10 - January 18, 2014 (Refers to the requirements presented in ANSI/ASHRAE 135-2012, Clause 15.8.2, relating to ReadRange executed with a Range parameter of 'byTime'.)

Interpretation 135-2012-11 - January 18, 2014 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2012, Clause 12.25.14, regarding all logging objects (TL, TLM, EL).)

Interpretation 135-2012-12 - April 9, 2014 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2012, Clause 5, regarding all Property MaxSegmentsAccepted, Client State Machine.)

Interpretation 135-2012-13 - January 24, 2015 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2012, Clause 19.1.3.3, regarding file objects using record-access.)

Interpretation 135-2012-14 - January 24, 2015 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2012, Clause 19.1.3.3, regarding restoring the configuration files.)

Interpretation 135-2012-15 - January 24, 2015 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2012, Clause 15.8, regarding ReadRange Service, by position with negative count.)

Interpretation 135-2012-16 - April 30, 2015 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2012, Clause 13.7, regarding UnconfirmedCOVNotification Service, K1-11 BIBB DS-COV-A.)

Interpretation 135-2012-17 - April 30, 2015 (Refers to the requirements presented in ANSI/ASHRAE 135-2012, Clauses 12.25.14, 12.30.19, and 21 (BACnetLogData and BACnetLogRecord) relating to trending.)

Interpretation 135-2012-18 - November 4, 2015 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2012, Clause 13.14, regarding SubscribeCOV service with indefinite lifetime.)

Interpretation 135-2012-19 - November 4, 2015 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2012, Clauses 12.12.8, 15.3.1.3.1, 15.9.1.3.1 and 15.10.1.3.1, regarding error returned to a CreateObject service.)

Interpretation 135-2012-20 - April 19, 2016 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2012, Clause 12.11.39, regarding Optionality of COV_Increment in Active_COV_Subscriptions.)

Interpretations of 135-2016

Interpretation 135-2016-1 - July 21, 2016 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2016, Clause 12.56, regarding the Network Port object.)

Interpretation 135-2016-2 - October 25, 2016 (Refers to the requirements presented in ANSI/ASHRAE Standard 135-2016, Clause 13.3.6, regarding the direct transitions.)