VIKEFON Bluetooth 5.0 Audio Transmitter Receiver

1. Introduction

The VIKEFON BT-B22 / BT-B21 is a versatile 3-in-1 Bluetooth 5.0 audio adapter designed to bring wireless audio capabilities to your existing devices. It functions as a Bluetooth Transmitter (TX), Receiver (RX), and a Bypass device, allowing seamless integration with various audio systems. Equipped with advanced CSR8675 chipset, aptX HD, and aptX Low Latency technologies, it ensures high-fidelity sound with minimal delay over an extended range.

Figure 1: VIKEFON BT-B22 / BT-B21 Bluetooth Audio Adapter

2. Package Contents

Please check the box for the following items:

• 1 x Bluetooth Transmitter/Receiver Adapter (BT-B22 or BT-B21)
• 1 x Micro USB charging cable (0.5m/19.6in)
• 1 x 3.5mm audio cable (0.5m/19.6in)
• 1 x 3.5mm jack to 2 RCA plug cables
• 1 x Digital Optical Toslink Audio Cable (1m/39.4in)
• 1 x User Manual

Figure 2: Included accessories and adapter

3. Key Features

• 3-in-1 Functionality: Supports Transmitter (TX), Receiver (RX), and Bypass modes.
• Bluetooth 5.0 Technology: Provides stable and efficient wireless connection.
• CSR8675 High-End Chip: Ensures superior sound quality.
• aptX HD: Delivers high-fidelity lossless sound quality in both RX and TX modes.
• aptX Low Latency (LL): Virtually eliminates audio-visual lag for synchronized media experience.
• Extended Range: Up to 80 meters (262 feet) line-of-sight in open air, 25-35 meters (80-110 feet) indoors.
• Dual Link: Connects to two Bluetooth headphones or speakers simultaneously.
• NFC Function: Simplifies pairing in RX mode for compatible mobile phones.
• Multiple Audio Connections: Digital Optical Toslink, 3.5mm AUX, and RCA.
• Long Battery Life: Built-in 1000mAh battery offers up to 15 hours in TX mode and 20 hours in RX mode.
• Volume Control: Integrated volume adjustment function.

Figure 3: The advanced CSR8675 chipset for stable and efficient performance.

Figure 4: Enjoy CD-like sound quality with aptX HD technology.

4. Controls and Indicators

Familiarize yourself with the device's layout:

Figure 5: Front and rear panel overview with controls and ports.

• ON/OFF Switch: Powers the device on or off.
• Mode Switching (ON/OFF RX Bypass TX): Selects between Receiver (RX), Bypass, and Transmitter (TX) modes.
• Indicator Lights: Show current mode (RX, TX), connection type (OPT, AUX), and codec (APTX, LL, HD, SBC).
• NFC Induction Area: For quick pairing with NFC-enabled devices in RX mode.
• Pre/Next Switch & Volume Up/Down: Controls track selection and volume.
• Play/Pause Button: Controls media playback.
• Quick Pairing Mode Button: Initiates pairing.
• 3.5mm AUX TX Input: Audio input for Transmitter mode.
• OPTICAL In (TX): Optical audio input for Transmitter mode.
• Charging Port: Micro USB port for charging.
• OPTICAL In (RX): Optical audio input for Receiver mode.
• 3.5mm AUX RX Input: Audio input for Receiver mode.

5. Setup and Operation

5.1. Charging the Device

Before first use, fully charge the adapter using the provided Micro USB cable and a standard USB power adapter (not included). The built-in 1000mAh battery takes approximately 4.5 hours to fully charge.

Figure 6: Battery life overview: 20 hours in RX mode, 15 hours in TX mode.

5.2. Power On/Off

Slide the ON/OFF switch to the 'ON' position to power on the device. Slide it to 'OFF' to power off.

5.3. Mode Selection

Use the 'ON/OFF RX Bypass TX' switch to select the desired operating mode:

• RX (Receiver) Mode: For receiving Bluetooth audio from your phone/PC and outputting to wired speakers/stereo.
• TX (Transmitter) Mode: For transmitting audio from non-Bluetooth devices (TV, PC) to Bluetooth headphones/speakers.
• Bypass Mode: Allows direct audio pass-through from input to output without Bluetooth processing.

5.4. Pairing in Receiver (RX) Mode

In RX mode, the device receives Bluetooth audio from your mobile phone, computer, or tablet and outputs it to your home stereo or speakers via AUX, Optical, or RCA cables.

1. Set the mode switch to 'RX'.
2. Connect the adapter to your audio system (e.g., speakers) using the appropriate cable (3.5mm AUX, Optical, or RCA).
3. The adapter will automatically enter pairing mode (indicator light will flash).
4. On your Bluetooth-enabled device (phone, PC), search for 'VIKEFON BT-B22' or 'BT-B21' in the Bluetooth settings and connect.
5. Alternatively, for NFC-enabled phones, simply tap your phone to the NFC induction area on the adapter for quick pairing.

Figure 7: Connecting your phone/laptop to speakers via the adapter in RX mode.

5.5. Pairing in Transmitter (TX) Mode

In TX mode, the device streams audio from your non-Bluetooth devices (TV, PC, iPod) to your Bluetooth headphones or speakers.

1. Set the mode switch to 'TX'.
2. Connect the adapter to your audio source (e.g., TV) using the appropriate cable (3.5mm AUX or Optical).
3. Ensure your Bluetooth headphones or speakers are in pairing mode.
4. The adapter will automatically search for and connect to nearby Bluetooth audio devices. You can also press the Quick Pairing Mode button to initiate pairing.
5. The indicator light will show a solid blue when connected.
6. The adapter supports connecting to two Bluetooth headphones simultaneously. After connecting the first, put the second headphone into pairing mode and press the Quick Pairing Mode button on the adapter again.

Figure 8: Streaming audio from your TV to Bluetooth headphones in TX mode.

Figure 9: Enjoying TV audio with two Bluetooth headphones simultaneously.

5.6. Bypass Mode

Bypass mode allows you to connect the adapter to your TV and convert the sound to a speaker device, while also offering Bluetooth connectivity. This design allows you to freely switch between Bypass mode and Bluetooth mode without disconnecting any cables.

1. Connect your audio source (e.g., TV) to the adapter's input.
2. Connect your wired speakers or soundbar to the adapter's output.
3. Set the mode switch to 'Bypass'. Audio will pass directly from the source to the speakers.
4. You can then switch to TX or RX mode as needed without re-cabling.

Figure 10: Direct audio connection with optional Bluetooth functionality.

Figure 11: Overview of Transmitter, Receiver, and Bypass modes.

6. Specifications

Figure 12: Illustrative diagram of the device's long-range Bluetooth transmission capability.

7. Troubleshooting

7.1. Audio Delay (Lip-Sync Issues)

If you experience audio delay when watching TV or movies, ensure both the VIKEFON adapter and your receiving Bluetooth headphones/speakers support aptX Low Latency (LL). If your receiving device does not support aptX LL, there may be a slight delay. The adapter will default to the best available codec.

Figure 13: Latency comparison of different Bluetooth codecs, highlighting aptX LL for minimal delay.

7.2. Difficulty Pairing with Sony Bluetooth Devices

Sony's Bluetooth headphones/earphones/speakers sometimes use a special encoding method that can cause longer pairing times with third-party devices like this adapter. While it may take longer, they should eventually pair successfully. Patience is key during the pairing process with Sony devices.

7.3. Device Enters Dormant Mode

The adapter is designed to conserve power. It will automatically enter dormant and power-saving mode after 6 minutes of no connection. To reactivate, simply press any button or reconnect a device.

7.4. Low Latency Not Activating (SBC only)

If the device only shows SBC codec when transferring via auxiliary input and you expect aptX LL, ensure your connected Bluetooth headphones also support aptX LL. Both the transmitter and receiver must support the same low-latency codec for it to activate. Check the indicator lights on the adapter to confirm the active codec.

7.5. No Volume Control

The adapter has integrated volume control buttons. If your connected device (e.g., older speakers) does not have its own volume controls, you can use the adapter's volume buttons to adjust the audio output level.

7.6. Limited Transmission Range

While the device offers a long range, actual performance can be affected by environmental factors. Obstacles like walls, and interference from other wireless devices (e.g., Wi-Fi routers, wireless TV adapters) can reduce the effective range. Try to minimize obstructions and interference sources for optimal performance.

8. User Tips

• For the best audio experience with minimal delay, ensure both your VIKEFON adapter and your Bluetooth headphones/speakers support aptX Low Latency.
• When using NFC for pairing in RX mode, make sure your mobile phone's NFC function is enabled.
• If you need to stream to two headphones, pair the first one, then put the second into pairing mode and press the quick pairing button on the adapter.
• Keep the adapter away from strong Wi-Fi routers or other wireless interference sources to maximize transmission range.
• The adapter can be used while charging, providing continuous operation.

9. Warranty and Support

This product comes with a 12-month manufacturer's limited warranty for defective items from the date of receipt. Accessories typically come with a 3-month warranty. Please retain your proof of purchase for warranty claims.

For technical support or warranty inquiries, please contact your retailer or the manufacturer directly. Do not attempt to repair the device yourself, as this may void the warranty.