1. Introduction
Welcome to the user manual for your Thomson RT850BT Bluetooth Speaker, FM Radio, and Alarm Clock. This guide provides detailed instructions on how to set up, operate, and maintain your device. Please read this manual thoroughly before use to ensure proper functionality and to maximize your experience with the RT850BT.
2. Safety Information
To ensure safe operation and prevent damage, please observe the following safety precautions:
- Do not expose the unit to rain, moisture, or extreme temperatures.
- Avoid placing the unit near heat sources or in direct sunlight.
- Ensure proper ventilation; do not block any ventilation openings.
- Use only the provided power adapter.
- Do not attempt to disassemble or modify the unit. Refer all servicing to qualified personnel.
- Keep the unit away from strong magnetic fields.
3. Package Contents
Verify that all items are present in the package:
- Thomson RT850BT Unit
- Power Adapter
- User Manual

Image: Thomson RT850BT packaging, illustrating the product and its key features.
4. Product Overview
4.1 Front Panel

Image: Front view of the Thomson RT850BT unit, showing the LCD display, speakers, and control buttons.
- LCD Display: Shows time, mode, and other information.
- /MODE Button: Power On/Off, switch between modes (Bluetooth, FM, AUX).
- /SLEEP/ZZ Button: Set sleep timer, activate snooze.
- /MEM Button: Set alarm, save/recall radio stations.
- </PREV Button: Previous track (Bluetooth), tune down (FM).
- /SCAN Button: Play/Pause (Bluetooth), auto scan (FM).
- >/NEXT Button: Next track (Bluetooth), tune up (FM).
- VOLUME- Button: Decrease volume.
- VOLUME+ Button: Increase volume.
4.2 Rear Panel

Image: Rear view of the Thomson RT850BT, highlighting the power supply, Line In (AUX-IN), and USB-C charge output ports.
- Power Supply (DC IN 5V): Connect the provided power adapter.
- Line In (AUX-IN): 3.5mm audio input for external devices.
- Charge Output (USB-C): USB Type-C port for charging external devices.
5. Setup
5.1 Power Connection
- Connect the power adapter to the DC IN 5V port on the rear of the RT850BT.
- Plug the power adapter into a standard wall outlet.
- The unit will power on automatically or enter standby mode.
5.2 Initial Power On and Clock Setting

Image: Close-up of the RT850BT's LCD display showing the time, 10:50 PM, and the 'PM' indicator.
- If the unit is in standby, press the /MODE button to turn it on.
- To set the clock, press and hold the /MEM button until the time display flashes.
- Use the </PREV and >/NEXT buttons to adjust the hour. Press /MEM to confirm.
- Use the </PREV and >/NEXT buttons to adjust the minute. Press /MEM to confirm.
- The clock is now set.
6. Operating Instructions
6.1 Bluetooth Mode

Image: Close-up of the RT850BT's LCD display indicating 'bt' for Bluetooth mode, along with the current time.
- Press the /MODE button repeatedly until 'bt' appears on the display. The unit is now in Bluetooth pairing mode.
- On your mobile device, enable Bluetooth and search for available devices.
- Select 'RT850BT' from the list to pair. A confirmation tone will sound upon successful connection.
- You can now play audio from your device through the RT850BT.
- Use the /SCAN button to Play/Pause, and </PREV / >/NEXT buttons to skip tracks.
- Adjust volume using the VOLUME- and VOLUME+ buttons.
6.2 FM Radio Mode
- Press the /MODE button repeatedly until the FM frequency appears on the display.
- Auto Scan: Press and hold the /SCAN button to automatically scan and save available FM stations (up to 50 stations).
- Manual Tuning: Briefly press </PREV or >/NEXT to fine-tune the frequency. Press and hold to scan for the next available station.
- Recall Saved Stations: Briefly press the /MEM button to cycle through saved stations.
6.3 Alarm Clock Function
The RT850BT supports setting multiple alarms.
- In standby mode, press and hold the /MEM button until 'AL1' or 'AL2' flashes.
- Use </PREV and >/NEXT to set the alarm hour, then press /MEM to confirm.
- Repeat for minutes.
- Select the alarm source (Buzzer or FM Radio) using </PREV and >/NEXT, then press /MEM.
- To activate/deactivate an alarm, briefly press the /MEM button in standby mode to cycle through alarm settings (AL1 ON/OFF, AL2 ON/OFF).
- When the alarm sounds, press /SLEEP/ZZ for snooze (alarm will sound again after 9 minutes) or press /MODE to turn off the alarm for the day.
6.4 AUX-IN Mode
- Connect an external audio device (e.g., MP3 player, smartphone) to the 'Line In' (AUX-IN) port on the rear panel using a 3.5mm audio cable (not included).
- Press the /MODE button repeatedly until 'AUX' appears on the display.
- Audio from the connected device will now play through the RT850BT. Control playback from your external device.
6.5 Dimmer Function
The display brightness can be adjusted to three intensity levels.
- In any mode, briefly press the /SLEEP/ZZ button to cycle through the brightness levels.
6.6 Sleep Function
Set a timer for the unit to automatically turn off.
- While the unit is on, press the /SLEEP/ZZ button repeatedly to select the desired sleep timer duration (e.g., 15, 30, 60, 90 minutes, OFF).
- The unit will automatically power off after the selected time.
6.7 USB-C Charging Port
The USB-C port on the rear panel is for charging external devices.
- Connect your compatible device's USB-C charging cable to the 'Charge output' port.
- Ensure the RT850BT is powered on or in standby mode for charging functionality.
7. Maintenance
To maintain the performance and appearance of your RT850BT:
- Cleaning: Use a soft, dry cloth to clean the exterior. Do not use abrasive cleaners, waxes, or solvents.
- Storage: If storing the unit for an extended period, disconnect it from the power outlet and store it in a cool, dry place.
- Ventilation: Ensure the ventilation grilles are free from dust and obstructions.
8. Troubleshooting
If you encounter issues with your RT850BT, refer to the following table for common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| No power | Power adapter not connected or faulty outlet. | Ensure power adapter is securely connected and the outlet is functional. |
| No sound | Volume too low, incorrect mode, or device not paired (Bluetooth). | Increase volume. Check if the correct mode (BT, FM, AUX) is selected. Re-pair Bluetooth device. |
| Bluetooth pairing fails | Device too far, Bluetooth not enabled on source, or RT850BT not in pairing mode. | Ensure devices are within range. Enable Bluetooth on your device. Set RT850BT to 'bt' mode. |
| Poor FM reception | Weak signal. | Adjust the unit's position to improve reception. |
| Alarm does not sound | Alarm not activated or set incorrectly. | Verify alarm settings and ensure it is set to ON. |
9. Specifications
- Model: RT850BT
- Bluetooth Version: 5.3
- Radio Tuner: FM (87.5-108 MHz)
- Station Memory: 50 FM stations
- Audio Input: AUX-IN (3.5mm)
- Display: LCD with 3-intensity dimmer
- Power Output: 30W Total Music Power
- Charging Port: USB-C (for external devices)
- Power Source: Corded Electric (DC 5V)
- Weight: 600 Grams
10. Warranty and Support
For warranty information and technical support, please refer to the documentation provided at the time of purchase or contact your local Thomson customer service. Keep your proof of purchase for warranty claims.





