Protocols & Profiles

Core Specification

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The main Bluetooth specification document defining all layers from PHY to profiles, versioned as 4.0, 5.0, 5.4, 6.0, etc.

    


    
    
    

      Also known as:
      
      Core Spec
      
    

    
  


  




  
  

    
Core Specification


The Bluetooth Core Specification is the master technical document published by the Bluetooth SIG that defines every layer of the Bluetooth protocol stack -- from the physical radio to application-level profiles. It is the authoritative reference for silicon vendors, firmware engineers, and product developers working with Bluetooth Low Energy and Bluetooth Classic.


Version History






Version
Year
Key BLE Features






4.0
2010
BLE introduced, GATT, ATT




4.1
2013
Dual-mode topology, L2CAP CoC




4.2
2014
DLE, LESC, LE Privacy




5.0
2016
LE 2M PHY, LE Coded PHY, Extended Advertising




5.1
2019
Direction Finding (AoA/AoD)




5.2
2020
LE Audio, Isochronous Channels, EATT




5.3
2021
Connection Subrating, channel classification




5.4
2023
PAwR (advertising/" class="glossary-term-link" data-term="Periodic Advertising" data-definition="Connectionless data broadcasting at fixed intervals." data-category="GAP & Advertising">Periodic Advertising with Responses)




6.0
2024
Channel Sounding, Decision-Based Advertising Filtering






Document Structure


The Core Specification is organized into volumes:


    

  • Volume 1: Architecture overview and terminology
    • 

  • Volume 2: BR/EDR Controller (Classic)
    • 

  • Volume 3: Host (L2CAP, SDP, GAP, ATT">GATT, ATT, SMP)
    • 

  • Volume 4: HCI (Host Controller Interface)
    • 

  • Volume 6: LE Controller (Link Layer, PHY)
    • 

  • Volume 7: Mesh (added in Mesh Profile 1.0)
    • 



How to Use the Spec


For BLE product development, the most referenced sections are Volume 3 Part G (GATT), Volume 6 Part B (Link Layer), and the relevant adopted profile specifications. Chip vendors' SDKs abstract most specification details, but understanding the spec is essential when debugging interoperability issues, interpreting HCI logs, or implementing custom profiles.


The specification is freely available for download from the Bluetooth SIG website after creating an Adopter account.

  

  

  
  
  




  
  
Related Terms

  

  

    
    Bluetooth SIG
    
  





  

  
  

  
  

  
  
  

    
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Frequently Asked Questions


  

    
    

      
      

        
Our glossary covers 90+ BLE technical terms organized by category. Each term includes a definition, related terms, and links to relevant chips and guides.