MR278 Bluetooth 5.3 Audio Transmitter User Manual

The MR278 Bluetooth 5.3 audio transmitter is a brand-new, multi-protocol device offering lossless audio transmission with low latency. It supports a variety of audio input sources, including USB, AUX, optical fiber, and coaxial connections. With Bluetooth protocols such as SBC, the APTX series of audio codecs, LC3, and Broadcast Audio, it can easily pair with and connect to wireless Bluetooth audio devices, including headphones and speakers. Its wide range of application scenarios encompasses home entertainment, gaming entertainment, and office meetings, enabling wireless transmission of audio signals and enhancing both convenience and comfort in use.

I. LED Indicator Definitions

Work Mode Indicators:

• “BA” Light On: The device is in BroadCast work mode.
• “LE” Light On: The device is in LE audio work mode.
• “BT” Light On: The device is in standard Bluetooth work mode.
• “BT” Light Flashes Once per Second: The device is in reconnecting state.
• “BT” Light Flashes Three Times per Second: The device is in Bluetooth search and pairing state.
• “BT” Light Steady On: The device is connected to a Bluetooth device.

Status Indicators:

• “USB”, “AUX”, “OPT”, “COAX” Lights On: The device is working on the corresponding audio input channel.
• CODE RGB Light On: The color corresponds to SBC (dark blue), aptX (light blue), aptX HD (green), Aptx adaptive high quality (yellow), Aptx adaptive low latency (purple).
• “Lossless”, “LE-LL”, “LE-HQ” Lights On: The device is working in the corresponding LE audio format.
• “Lightning Bolt” Symbol Light: Steady on during charging, turns off automatically when fully charged; flashes when battery is low, and stops flashing after connecting the charging cable.

II. Functional Operations

Power On/Mode Switching:

• Move the BA-BT switch on the device to the BT end to power on the device and enter standard Bluetooth and LE audio work modes.
• Move the BA-BT switch on the device to the BA end to power on the device and enter BroadCast work mode.

Device Powers On into Reconnecting State:

• If the device has connection records, it will automatically enter the reconnecting state after powering on.

Enter Pairing State:

• After powering on the device in BT mode, double-click the double-arrow pairing button to enter the search and pairing state.

Clear Paired Devices:

• With the device powered on, long-press the double-arrow button for 8 seconds. All LED lights will turn on simultaneously, indicating successful clearing of paired devices.

USB/AUX/OPT/COAX Audio Input:

• Click the audio input mode switching button on the device to switch between USB, AUX, OPT, and COAX audio sources.

Audio Encoding Format Switching:

• During BT mode connection and usage, double-click the audio input mode switching button to cycle through and switch the transmitted audio encoding format.

Automatic Power-Off Function:

• The device will automatically power off after 15 minutes of inactivity and needs to be powered on again to wake it up.

Volume Adjustment:

• While the device is connected and in use, click the “+” and “-” buttons to adjust the volume.

BT Mode Operation Steps:
A. Power on the Bluetooth speaker or headphones to be connected and set them to pairing mode.
B. Move the BA-BT switch on the device to the BT end to power on the device and enter standard Bluetooth and LE audio work modes.
C. Insert the corresponding audio cable and switch the device’s audio channel to the corresponding indicator light on; adjust the TV’s optical or coaxial output audio format to PCM; for computer USB connections, set our sound card MR278 as the default output in the computer’s control panel sound settings, and disable other sound cards.
D. Double-click the double-arrow pairing button to enter the search and pairing state. The “BT” light on the device will flash rapidly (three times per second).
E. After successful connection, the corresponding audio encoding light on the device will turn on, and the Bluetooth speaker or headphones will emit sound.

BA Mode Operation Steps:
A. Move the BA-BT switch on the device to the BA end to power on the device and enter BroadCast work mode.
B. Insert the corresponding audio cable and switch the device’s audio channel to the corresponding indicator light on; adjust the TV’s optical or coaxial output audio format to PCM; for computer USB connections, set our sound card MR278 as the default output in the computer’s control panel sound settings, and disable other sound cards. When using the phone’s OTG function, ensure music is playing on the phone before connecting to Bluetooth for normal playback.
C. Turn on the Bluetooth device (Bluetooth headphones or speakers) and enter BroadCast mode. The device will automatically pair and connect.
D. After successful connection, the headphones or speakers will emit sound.

III. Charging

Charging Method:

• Insert one end of the USB charging cable into the device’s charging port and the other end into a standard USB 5V power outlet (it is recommended to use a charger with an output voltage of 5V 1A (do not use a variable voltage fast charger)).
• The charging time is approximately 2.5 hours. The red light stays on during charging and turns off after completion.

Notes:

• When the battery is low or the charging power source is of poor quality, current interference noise may occur during use.
• Try not to store the device with a low battery. Long-term storage with a low battery may cause the battery to automatically protect itself and fail to supply power.
• When using the device while charging, current interference noise may occur. Removing the charging cable can solve this issue.

IV. Product Parameters

• Brand: Ayin
• Model: MR278
• Bluetooth Version: V5.3
• Bluetooth Protocols: SBC\APTX series audio\LC3\Broadcast Audio
• Power Class: Class 1, Class 2
• Input/Output Interfaces: Optical/Coaxial/USB/AUX
• Effective Range: >80M (Class 1 actual measurement)
• BT Mode: Standard Bluetooth function, LE audio function
• BA Mode: Broadcast Audio
• Connection Characteristics: BT mode one-to-one, BA mode one-to-N
• Working Time: BT > 15 hours, BA > 8 hours
• Battery Capacity: 1000mAh
• Charging Time: Approximately 2.5 hours
• Input Voltage: DC 5V
• Product Dimensions: 1207022mm

V. Troubleshooting

Adapter Not Working Properly:

• Check if the device’s battery is low. You can try connecting the charging cable and powering on the device again. The indicator light should turn on to indicate power-on.
• If you cannot search for Bluetooth devices (Bluetooth headphones or speakers), check if the device is in the search and pairing state. The “BT” light should flash rapidly (three times per second) during this state.
• The device’s work mode and status can be determined based on the LED indicator lights.
• If there is no sound after connection, check if the device’s audio interface corresponds to the device’s audio channel. This can be determined based on the LED indicator lights.
• If there are audio interruptions or stuttering during use, try restarting the transmitter device or Bluetooth headphones.

Other Notes:

• Do not place the device on metal objects. It should be placed in front of the TV without any obstructions.
• Do not open the cover or touch any components inside the device.