The LE Audio specification introduces the Coordinated Set Identification Service (CAS) to manage multi-device audio streaming. A key challenge is ensuring SDP interoperability between LE Audio and classic Bluetooth BR/EDR stacks. This article breaks down the specific SDP records, attribute IDs, and service discovery procedures required for CAS to function correctly across both radio types. It covers mandatory SDP entries, UUID mapping rules, and the handshake sequence that allows a classic Bluetooth host to discover and identify an LE Audio CAS device. For developers working on Bluetooth audio products, mastering these interop rules is essential to avoid device pairing failures and ensure a smooth user experience in multi-device scenarios. The article also discusses common pitfalls and testing strategies for validating SDP compliance.
This article provides a detailed technical explanation of the SDP interoperability rules for LE Audio CAS, critical for enabling seamless discovery between LE Audio devices and classic Bluetooth stacks.