What a BIBB Is
A BIBB, a BACnet Interoperability Building Block, is a named unit of capability defined in Annex K of ANSI/ASHRAE 135-2024. Each BIBB pairs a role with the BACnet services it must perform in a given direction, for example “can answer read requests” (DS-RP-B) or “can send a discovery broadcast” (DM-DDB-A).
BIBBs are the building blocks of device profiles: a profile such as B-BC is defined as the set of BIBBs a device must implement to claim it. A device documents which BIBBs it supports in its PICS (Protocol Implementation Conformance Statement).
How to Read a BIBB Code
A BIBB code has three parts: an interoperability-area prefix, a function name, and a role letter.
| Part | Meaning | Examples |
|---|---|---|
| Area prefix | The interoperability area | DS data sharing, AE alarm and event, SCHED scheduling, T trending, DM device management, NM network management |
| Function | The specific capability | RP ReadProperty, COV change of value, DDB dynamic device binding |
| Role letter | Which side of the exchange | -A initiates (the client side), -B executes (the server side) |
So DS-RP-B is “Data Sharing, ReadProperty, B side”: a device that answers ReadProperty requests. The device profiles show, per profile, exactly which BIBBs are required and therefore which services the device must initiate and execute.
BACnet Secure Connect BIBBs
The network-management BIBBs behind BACnet Secure Connect have dedicated reference pages.
| BIBB | Role |
|---|---|
| NM-SCH-B | Secure Connect Hub: the message-fanout function that carries the BACnet SC datalink messages |
| NM-SCDC-B | Secure Connect Direct Connect: the optional node-to-node path that bypasses the hub |
| NM-SCCM-A | Secure Connect Certificate Management: provisioning and rotating device certificates |
The BIBB codes named across the device profiles (DS-RP-B, AE-N-I-B, SCHED-I-B, and the rest) map through Annex K to the services each profile requires.
Alarm and Event BIBBs
The BIBBs behind intrinsic event notification also have dedicated reference pages.
| BIBB | Role |
|---|---|
| AE-N-I-B | Originate a notification from intrinsic reporting on the device’s own objects |
| AE-N-E-B | Originate a notification through an Event Enrollment object watching another device |
| AE-N-A | Receive event notifications, the operator-workstation side |
| AE-ACK-A | Initiate AcknowledgeAlarm on an operator’s behalf |
| AE-ACK-B | Execute AcknowledgeAlarm and record the acknowledgment against the originating object |
Scheduling BIBBs
The BIBBs behind BACnet scheduling also have dedicated reference pages.
| BIBB | Role |
|---|---|
| SCHED-I-B | A Schedule writes its own locally-hosted objects |
| SCHED-E-B | A Schedule writes to objects hosted on remote devices |
Device Management BIBBs
The BIBBs behind device restart and recovery also have dedicated reference pages.
| BIBB | Role |
|---|---|
| DM-DCC-B | Execute DeviceCommunicationControl, silencing the device on request |
| DM-RD-B | Execute ReinitializeDevice across its restart and backup/restore states |
| DM-LM-B | Execute AddListElement and RemoveListElement against list-typed properties |
| DM-TS-B | Accept TimeSynchronization and update the device clock |
Networking BIBBs
The BIBBs behind how BACnet networks scale also have dedicated reference pages.
| BIBB | Role |
|---|---|
| NM-BBMDC-B | Execute BDT reads/writes and FDT reads as a BACnet BBMD |
| NM-FDR-A | Register into a remote BBMD’s Foreign Device Table |
| NM-RC-B | Answer the network-layer router peer messages |