Model 5125 Key benefits Supports multiple codecs for flexible wireless audio including AAC, aptX LL, aptX HD, and LDAC for improved compatibility and sound quality. Hardware button control with a clear, repeatable key layout (KCOM, PLAY, VOL+, VOL, P/V, +, MODE) for intuitive operation without needing to access software. Ready for integration with enclosures or boxes, negotiating the Bluetooth protocol LDAC by default (5125) to maximize audio performance. Clear pairing management and easy through a serial AT command interface and Android app. Android app enables user level of Bluetooth name (multilanguage support), pairing password, EQ settings, and prompt tone, without requiring device firmware changes. Visual and electrical status indicators for system monitoring via the BT_HL signal and differential analog outputs for precise audio transport. Core specifications Codecs supported: AAC, aptX LL, aptX HD, LDAC protocol when used with a box: LDAC, default 5125 Clear pairing information: supported Serial control: AT commands via serial port, 115200 baud, 8 data bits, no parity, 1 stop bit (115200, N, 8, 1) Android app capabilities: modify Bluetooth name (multilanguage), pairing password, custom EQ, switch prompt tone Output level: level 3.3 V is valid Bluetooth status indicator: BT_HL pin outputs 3.3 V when connected; 0 V when disconnected Analog outputs: differential RP, RN, LP, LN Use scenarios Car or home audio DAC integration Use the 5125 as a Bluetooth audio input with LDAC/aptX/AAC support to feed a car stereo or home amplifier via differential outputs Adjust EQ and Bluetooth device name via Android app; monitor connection via BT_HL Use the AT command interface for automation or scripted configuration when integrating with other car or home audio components Desktop/PC Bluetooth bridge Connect to a desktop or media PC to stream fidelity audio to an external DAC or amplifier Use the serial AT commands for scripted setup or remote control; pairing and name as needed through the Android app DIY audio projects with robust signaling Differential outputs RP/RN and LP/LN facilitate ‑quality audio paths to amplifiers or dedicated DAC stages BT_HL signaling provides a simple method to monitor connection status in embedded systems Clear pairing information and LDAC capability help ensure stable wireless performance in custom builds Notes The device is designed to maintain the stated functions and specifications without introducing additional features beyond those described. All terminology and values reflect the original model capabilities and intended use cases.