eppfun Bluetooth 5.3 Audio Receiver Transmitter Adapter (Model B55) User Manual

1. Introduction

The eppfun B55 is a versatile Bluetooth 5.3 audio receiver and transmitter adapter designed to upgrade your audio experience. It supports aptX HD, aptX LL, and aptX Adaptive codecs, ensuring high-quality, low-latency wireless audio. This device can function in two primary modes: Receiver (RX) mode to stream audio from your phone/computer to wired speakers, and Transmitter (TX) mode to send audio from non-Bluetooth devices (like TVs or computers) to Bluetooth headphones or speakers. It also supports connecting up to two devices simultaneously in TX mode.

eppfun B55 Bluetooth 5.3 Audio Receiver Transmitter Adapter with antenna — eppfun B55 Bluetooth 5.3 Audio Receiver Transmitter Adapter, highlighting Bluetooth 5.3, Receiver Mode, Transmitter Mode, aptx-LL/HD/Adaptive, and Connect 2 devices features.

2. Package Contents

Please check the package for the following items:

eppfun B55 Bluetooth Adapter
3.5mm Audio Cable
USB-C Cable (for power)
User Manual (this document)

3. Product Overview and Interfaces

Diagram of eppfun B55 product parameters and interfaces — Detailed view of the eppfun B55 adapter showing dimensions (100mm height, 50mm width, 70mm depth, 22mm thickness), USB-C power input, 3.5mm RX input, and 3.5mm TX input. The front panel features a Play/Pause button and LED indicators (A and B). Double-click to enter search, long press for 5 seconds to reset.

USB-C Power Input: For connecting to a power source.
3.5mm RX Input: Audio input for Receiver mode.
3.5mm TX Input: Audio input for Transmitter mode.
Play/Pause Button: Controls audio playback. Double-click to enter search mode, long press for 5 seconds to reset.
LED Indicators (A and B): Indicate current mode and connection status.

4. Setup and Operation

4.1 Powering On/Off

Connect the USB-C cable to the adapter and a 5V USB power source (e.g., wall adapter, computer USB port). The device will power on automatically.
To power off, disconnect the USB-C cable.

4.2 Mode Selection (Automatic)

The device automatically switches between Transmitter (TX) and Receiver (RX) modes based on the audio cable connection:

TX Mode: When the audio cable is plugged into the TX interface, the device defaults to transmission mode.
RX Mode: When the audio cable is inserted into the RX interface, the device automatically switches to reception mode.

Connection diagram for TX and RX modes — Diagram illustrating TX Mode (Transmitter) and RX Mode (Receiver) connections. In TX mode, the device connects to TV, computer, or TV box via 3.5mm TX input, transmitting to Bluetooth speakers or headphones (TX mode A light on). In RX mode, the device connects to ordinary speakers, car audio, or power amplifiers via 3.5mm RX input, receiving from phone, Pad, or laptops (RX mode B light on).

4.3 Receiver (RX) Mode Operation

In RX mode, the B55 receives Bluetooth audio from your smartphone, tablet, or computer and outputs it to a wired audio system.

Connect the 3.5mm audio cable from the B55's RX input to your wired speaker, car audio system, or amplifier.
Ensure the B55 is powered on. The 'B' LED indicator should be lit.
On your smartphone or other Bluetooth-enabled device, search for "eppfun B55" in the Bluetooth settings and pair with it.
Once connected, audio from your device will stream wirelessly to your wired audio system.

RX Mode connection to wireless speaker — Illustration of the eppfun B55 in RX Mode, connecting a smartphone to a traditional speaker system, upgrading it to wireless audio.

RX Mode connection to car speaker — Illustration of the eppfun B55 in RX Mode, connecting a smartphone to a car's AUX input, enabling wireless audio streaming in the car. Note: Connecting AUX interface devices requires USB power supply.

4.4 Transmitter (TX) Mode Operation

In TX mode, the B55 transmits audio from non-Bluetooth devices to Bluetooth headphones or speakers.

Connect the 3.5mm audio cable from your audio source (e.g., TV, computer, TV box) to the B55's TX input.
Ensure the B55 is powered on. The 'A' LED indicator should be lit.
Put your Bluetooth headphones or speaker into pairing mode.
Double-click the Play/Pause button on the B55 to enter search mode. The B55 will automatically search for and connect to nearby Bluetooth receiving devices.
Once connected, audio from your source device will stream wirelessly to your Bluetooth headphones/speaker.

TX Mode connection to computer and headphones — Illustration of the eppfun B55 in TX Mode, connecting to a laptop via USB to output a wireless signal to Bluetooth headphones or earbuds. Supports connecting one to two devices.

TX Mode connection to TV and wireless headphones — Illustration of the eppfun B55 in TX Mode, connecting to a TV to transmit audio to two pairs of wireless Bluetooth headphones, allowing shared listening.

4.5 Connecting Two Devices in TX Mode

The B55 supports connecting to two Bluetooth receiving devices simultaneously in TX mode (e.g., two pairs of headphones for shared TV viewing).

Connect the B55 to your audio source (e.g., TV) via the 3.5mm TX input.
Pair the first Bluetooth headphone/speaker as described in section 4.4.
Once the first device is connected, put the second Bluetooth headphone/speaker into pairing mode.
Double-click the Play/Pause button on the B55 again to search for and connect the second device.

5. Specifications

Feature	Specification
Product Model	B55
Bluetooth Version	5.3
Wireless Type	Bluetooth
Interface	3.5 MM, Type-C
Audio Interface	USB-C / 3.5mm AUX
Transmission Mode	Receive/Transmit (RX/TX)
Transmission Distance	≤ 20m (65ft)
Support Apt-x	Yes (aptX HD/LL/Adaptive)
Product Material	ABS material
Compatibility	Automatic downward compatibility recognition (V4.0, V4.1, V4.2, V5.0)

Bluetooth 5.3 chip with compatibility information — The B55 features a Bluetooth 5.3 chip, offering stable and faster signal transmission, rejecting delay and stuttering. It provides automatic downward compatibility with Bluetooth versions V4.0, V4.1, V4.2, and V5.0.

Wireless transmission range diagram — Diagram illustrating the 20-meter wireless transmission range of the eppfun B55, enabled by its external antenna for stable connection without signal interference.

Lossless decoding technology for high-definition audio — The device supports lossless decoding technology, including automatic adaptation of transmitter equipment (SBC/AAC/APTX/APTX LL/aptX HD/aptX Adaptive) and automatic reception adaptation (SBC/AAC/APTX/aptX HD/aptX Adaptive) for high-definition audio quality.

6. Troubleshooting

No Power: Ensure the USB-C cable is securely connected to a 5V power source. Try a different USB port or power adapter.
Cannot Pair:
- Ensure the B55 is in the correct mode (TX or RX) for your intended use.
- Make sure your receiving/transmitting device is in pairing mode.
- Double-click the Play/Pause button on the B55 to initiate search mode.
- Move the devices closer to each other.
- Long press the Play/Pause button for 5 seconds to reset the B55 and try pairing again.
No Audio:
- Check all audio cable connections (3.5mm).
- Ensure the volume on both the B55 and your connected audio devices is turned up.
- Verify that the B55 is successfully paired and connected to your desired device.
- Confirm the correct audio input/output is selected on your source/receiving device.
Audio Lag/Stuttering:
- Move the B55 and connected devices closer to reduce interference.
- Ensure there are no major obstructions (walls, large metal objects) between the devices.
- Minimize other wireless activity in the area.
- The B55 supports aptX LL/HD/Adaptive for low latency, ensure your connected device also supports these codecs for optimal performance.
Connecting Two Headphones in TX Mode: If you have trouble connecting a second pair of headphones, ensure the first pair is already connected, then put the second pair into pairing mode and double-click the B55's Play/Pause button to search for it.

7. Maintenance

Keep the device dry. Moisture can damage internal circuits.
Do not expose the device to extreme temperatures.
Avoid dropping or strong impacts, as this can damage the device.
Clean the device with a soft, dry cloth. Do not use harsh chemicals or detergents.
Store the device in a clean, dust-free environment when not in use.

8. User Tips

Dual Headphone Connection: Yes, you can connect two headphones via Bluetooth to watch TV in Transmitter (TX) mode. First, connect the B55 to your TV's audio output (e.g., 3.5mm headphone jack). Then, pair the first Bluetooth headphone. Once connected, put the second headphone into pairing mode and double-click the B55's Play/Pause button to connect it.
Car Use: When using the B55 in RX mode in a car, ensure it is powered via a USB port (e.g., car charger) as AUX interface devices typically require a power supply.
Optimal Range: For the best wireless performance and to avoid signal interference, try to keep the adapter within 20 meters (65 feet) of your connected Bluetooth devices.

9. Warranty and Support

For warranty information or technical support, please refer to the official eppfun website or contact your retailer. Keep your purchase receipt for warranty claims.