Bluetooth audio with LDAC as the protocol (LDAC 5125 default) and clear pairing information. Serial port AT command interface supported at 115200 baud, with 8 data bits, no parity, 1 stop bit (115200, N, 8, 1). Android app support for modifying Bluetooth name (supports any language), pairing password, custom EQ, and switchable prompt tone. Bluetooth connection status output enabled via BT_HL: Bluetooth connected outputs 3.3V, Bluetooth disconnected outputs 0V. Codec support on the 5125 module includes AAC, aptX LL, aptX HD, and LDAC. Function keys available: KCOM, PLAY, VOL+, VOL, P/V, +, MODE. level signals are valid at 3.3V. Analog differential output available: RP, RN, LP, LN. Use case: as a wireless Bluetooth DAC/bridge to connect a phone or computer to an external amplifier or powered speaker, enabling LDAC streaming and easy control via the Android app or AT commands. Use case: for DIY audio projects and development/testing, utilizing AT command control, codec negotiation, and programmable function keys to tailor behavior and testing scenarios. Use case: applications requiring configurable Bluetooth identity and security, with the Android app to set Bluetooth name, pairing password, and EQ, plus easily switchable prompt tones for different environments.