Bluetooth Classic
The original Bluetooth BR/EDR (Basic Rate/Enhanced Data Rate) technology for streaming audio, file transfer, and serial communication.
Bluetooth Classic
Bluetooth Classic, formally known as BR/EDR (Basic Rate / Enhanced Data Rate), is the original Bluetooth radio technology standardized in 1998. It operates in the same 2.4 GHz ISM band as BLE but uses a fundamentally different protocol stack optimized for continuous, higher-bandwidth data streams such as audio and file transfer.
How It Differs from BLE
While BLE is designed for intermittent, low-power data bursts, Bluetooth Classic maintains persistent radio connections and delivers throughput up to 3 Mbps with Enhanced Data Rate. This makes it the standard choice for A2DP stereo audio, HFP/HSP hands-free calling, Serial Port Profile (SPP) data transfer, and OBEX file exchange.
The power profile of Bluetooth Classic is correspondingly higher. Active current draw ranges from 30 to 100 mA depending on the data rate and output power, and idle connections still consume 1--20 mA. This rules out coin-cell-powered applications but is acceptable for rechargeable devices like headphones, speakers, and car infotainment systems.
Connection Model
Bluetooth Classic uses a master/slave scatternet topology. A master can connect to up to seven active slaves simultaneously. Device discovery uses an inquiry procedure that scans 79 channels (1 MHz each) using frequency hopping, which takes several seconds compared to BLE's sub-second advertising discovery. The protocol stack includes L2CAP for segmentation, RFCOMM for serial port emulation, and SDP for service discovery -- none of which are shared with BLE.
Coexistence with BLE and the Transition to LE Audio
Many modern devices are dual-mode, implementing both Classic and BLE stacks on the same radio hardware. A smartphone uses Classic for audio streaming to headphones while simultaneously using BLE to communicate with a fitness tracker. With the advent of LE Audio in Bluetooth 5.2, the primary use case for Classic -- audio streaming -- is migrating to BLE. LC3 codec and Auracast." data-category="LE Audio">LE Audio's LC3 codec offers better quality at half the bitrate, and Auracast enables broadcast audio scenarios that Classic cannot support. For new product designs, BLE and LE Audio are increasingly the preferred choice.
Related Terms
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