Communication Protocols Applications RFCOMM / SDP L2CAP (Logical Link Control and Adaptation Protocol) Host Controller Interface (HCI) Link Manager (LM) Baseband Radio Bluetooth Defines the requirements for the Bluetooth transceiver device. Manages physical channels and links (asynchronous and synchronous), handles packets, paging and inquiry to access Bluetooth devices in the area. Carries out link setup, authentication, link configuration, etc. Provides a command interface to the baseband controller and link manager, and access to hardware status and control registers. Provides connection-oriented and connectionless data services to upper layer protocols with protocol multiplexing capability, segmentation, and reassembly operation and group abstractions. RFCOMM: Provides emulation of serial ports over the L2CAP. SDP: Provides a means for applications to discover which services are available and to determine the characteristics of those available services Provides what application are able to run.