KCX_BT_EMITTER Bluetooth 5.3 Audio Transceiver Module Transmit & Receive 2-in-1 Board

📌 Product Overview

The KCX_BT_EMITTER is an all-in-one Bluetooth audio transceiver module integrated with Bluetooth stereo audio transmit and receive functions, adopting Bluetooth 5.3 core chip. It supports automatic reconnection to the last paired Bluetooth device, and serial AT command configuration to customize Bluetooth name, search nearby devices, connect/disconnect target compatible Bluetooth equipment. Users can switch transmit or receive mode easily by short-circuiting the onboard TX/RX solder pads, factory default is transmit mode (pads open). Equipped with red-blue dual color LED status indicator, LINK pin outputs 3.3V level signal when Bluetooth connected for external status detection. It supports stereo dual-channel audio input/output, built-in PCB antenna with reserved IPEX external antenna socket for extended transmission range. Wide working voltage 3.5V-5V, industrial stable performance -40℃ ~ +85℃ working temperature, widely used for wireless audio transmission, audio equipment DIY modification, speaker/headset audio upgrade, embedded audio projects.

🧠 Core Hardware Layout

1. Main Control Chip: Bluetooth 5.3 audio chip, low power consumption, stable audio transmission
2. Antenna Design: Dual antenna solution – onboard breakable PCB antenna + IPEX 2.4G external antenna interface
3. Status Indicator: Red & blue dual-color LED, different light prompt for transmit/receive mode and pairing status
4. Operation Button: Onboard PAIR pairing button, external CONNECT pin for extended key trigger
5. Mode Switch: TX/RX solder pads, open = transmit mode, shorted = receive mode
6. Peripheral Circuit: High-precision crystal oscillator, complete audio filter circuit, 11PIN 1.25mm stamp hole pin header for easy soldering wiring
7. USB Audio Function: DP/DM USB pins, can be recognized as USB Audio2.0 sound card when connected to PC USB port

⚙ Core Technical Specifications

• Model: KCX_BT_EMITTER
• Bluetooth Version: Bluetooth 5.3
• Default Bluetooth Name: Bluetooth Audio
• Dimension: 23.5 * 15.5mm
• Net Weight: 1g
• Operating Voltage: DC 3.5V ~ 5V
• Working Current: 35mA
• Max Transmission Distance: ≤20 meters (open space)
• RF Output Power: 5dBm
• RF Frequency Band: 2402MHz ~ 2480MHz
• Audio Parameter
  • Channel: 2CH Stereo
  • Frequency Response: 20Hz ~ 20KHz
  • Dynamic Range: 80dB
  • SNR: 95dB
  • Total Harmonic Distortion: -70dB
  • I/O Audio Amplitude: ≤2Vpp
  • Transmission Delay: 250 ~ 300ms
• Working Temperature: -40℃ ~ +85℃

📍 11Pin Pin Definition

Pin No.	Pin Name	Function Description
1	+5V	3.5V-5V power input pin
2	PGND	Power ground
3	LINK	Connection status pin: 3.3V output when paired, 0V when disconnected
4	RX	Serial UART receive pin, for AT command configuration
5	TX	Serial UART transmit pin, for AT command configuration
6	AUDIO_L	Left channel audio I/O port: Input audio signal (TX mode), Output audio signal (RX mode)
7	AUDIO_R	Right channel audio I/O port: Input audio signal (TX mode), Output audio signal (RX mode)
8	AGND	Audio signal ground
9	DP	USB D+ data line, USB sound card function
10	DM	USB D- data line, USB sound card function
11	CONNECT	External pairing button pin, same function as onboard PAIR button

✨ Dual Working Mode Introduction

1. Transmitter Mode (Factory Default, TX/RX pads open)

• Audio Input: AUDIO_L / AUDIO_R receives line audio signal from PC, MP3, player, audio source device
• Transmission Function: Wirelessly send stereo audio to this-series Bluetooth receiver modules; partial compatible Bluetooth headsets/speakers
• USB Sound Card Function: Connect DP/DM to computer USB, PC identifies USB Audio2.0 sound card, computer audio converts to Bluetooth wireless signal
• Light Prompt: Red LED flashes when unpaired, steady red light after successful Bluetooth connection

2. Receiver Mode (TX/RX solder pads shorted)

• Audio Output: AUDIO_L / AUDIO_R outputs stereo audio signal, directly drive headphones or connect power amplifier to speakers
• Connection Function: Pair with mobile phones, tablets to play Bluetooth wireless music
• Light Prompt: Blue LED flashes when unpaired, steady blue light after successful Bluetooth connection

🛠 Key Features

✅ Dual Mode Freely Switchable: Solder pads short/open to switch transmit / receive audio mode, factory default transmit mode ✅ Bluetooth 5.3 Low Latency: Stable long-distance transmission up to 20m, low audio delay 250-300ms, clear stereo sound ✅ Dual Antenna Optional: Onboard PCB antenna for simple use; IPEX socket to connect external 2.4G antenna for longer range ✅ AT Command Customization: UART serial port supports AT commands to rename Bluetooth, search devices, control pairing/disconnect ✅ Auto Reconnection: Automatically re-pair the last connected Bluetooth device after power on ✅ Dual Color LED Prompt: Distinct red/blue light identification for TX/RX mode and pairing status ✅ USB Audio Sound Card: DP/DM USB pins enable PC USB audio input without extra audio line ✅ Complete Stereo Audio Circuit: Left/Right dual channel, independent audio ground to reduce noise, high SNR 95dB ✅ External Expansion Pin: LINK status output pin + CONNECT external key pin for secondary development ✅ Wide Industrial Temperature: -40℃ ~ +85℃ stable operation for industrial audio equipment ✅ Compact Mini Size: 23.5*15.5mm tiny PCB, lightweight 1g, easy to embed into all audio devices

🛒 Application Scenarios

1. Wireless Audio Transmission: Pair two modules (one TX + one RX) to realize wired audio wireless transmission between audio devices
2. Audio Source Wireless Upgrade: Convert desktop computer, fixed audio player, TV wired audio to Bluetooth wireless output
3. Bluetooth Speaker DIY: Set module as receiver mode to receive mobile phone Bluetooth music, match power amplifier to build speaker
4. Wireless Headset Modification: Receiver mode output audio to drive earphones for custom Bluetooth headsets
5. USB Sound Card Wireless Transmit: PC USB connection to module, wirelessly transmit computer audio to Bluetooth receiving equipment
6. Industrial Embedded Audio: Instrument, monitoring equipment wireless audio output/collection

⚠ Important Compatibility Notice

1. When using transmitter mode, full compatibility is only guaranteed with our store’s own Bluetooth audio receiver modules. Compatibility with third-party Bluetooth headsets, speakers, car navigation systems is not guaranteed.
2. Cannot pair Bluetooth devices that require password verification; connection failure or no sound after pairing with third-party Bluetooth receivers is not covered by after-sales support.
3. Recommended matching usage: Two KCX_BT_EMITTER modules (one transmit, one receive) to achieve stable lossless wireless audio transmission.

📦 Package List

1 × KCX_BT_EMITTER Bluetooth Audio Transmit Receive All-in-one Module