What B-ACCR Is
A BACnet device profile is a standardized capability level: a checklist of things a device must be able to do before it can wear the label. B-ACCR (BACnet Access Control Credential Reader) is defined in Annex L of ANSI/ASHRAE 135-2024 (clause L.7.5) as a device that reads credentials (a card, fob, or PIN) and presents them as authentication factors through COV (Change of Value) reporting on a Credential Data Input object.
It is a Miscellaneous-family profile, so a device can claim it alongside a profile from another family. The checklist items are BACnet Interoperability Building Blocks (BIBBs); a device documents its claim in its PICS (Protocol Implementation Conformance Statement).
Where It’s Used
B-ACCR fits the reader at a door that captures a credential and passes it to the access decision.
- Card and fob readers. A reader presenting each swipe or tap as an authentication factor a controller evaluates.
- PIN pads and biometric readers. Any device that captures a credential and reports it over BACnet.
- Reader-to-controller integration. A reader whose credential events a separate access controller subscribes to by COV.
Required Services
The table below is the exhaustive service set required by the B-ACCR BIBBs. Initiates means the device sends the request or notification; Executes means the device receives and acts on it (responding, for confirmed services). BIBB codes encode the same split: a -A BIBB is the initiating side, a -B BIBB the executing side. A - means the profile does not require that direction; a device may still support it.
| Capability area | Service | Required by BIBB | Initiates | Executes |
|---|---|---|---|---|
| Data sharing | ReadProperty | DS-RP-B, DS-ACCDI-B | - | Yes |
| Data sharing | WriteProperty | DS-WP-B, DS-ACCDI-B | - | Yes |
| Data sharing | SubscribeCOV | DS-COV-B, DS-ACCDI-B | - | Yes |
| Data sharing | ConfirmedCOVNotification | DS-COV-B, DS-ACCDI-B | Yes | - |
| Data sharing | UnconfirmedCOVNotification | DS-COV-B, DS-ACCDI-B | Yes | - |
| Device and network management | Who-Is | DM-DDB-B | - | Yes |
| Device and network management | I-Am | DM-DDB-B | Yes | - |
| Device and network management | Who-Has | DM-DOB-B | - | Yes |
| Device and network management | I-Have | DM-DOB-B | Yes | - |
The credential input is a hosted object. The DS-ACCDI-B requirement means the device hosts at least one Credential Data Input object whose Present_Value reports the captured authentication factor, and which supports COV so a controller is notified the moment a credential is read.
Related Profiles
| Profile | How it differs from B-ACCR |
|---|---|
| B-ACDC | Access Control Door Controller: operates the door hardware rather than reading credentials |
| B-ACC | Access Control Controller: the full access controller that makes the access decision |
| B-SS | Smart Sensor: a general read-only device, without the credential object model |
What Chipkin Provides
The CAS BACnet Stack implements the Credential Data Input object with COV reporting and the services the B-ACCR profile requires. Talk to us about building or integrating a B-ACCR device on the stack.