UGREEN 35223 Bluetooth 5.2 AUX/RCA Transmitter/Receiver
Overview
UGREEN 35223 is a rechargeable Bluetooth 5.2 transmitter/receiver with a 3.5mm port and a cable kit for AUX and stereo RCA equipment. Below: direction, pairing, codec limits, microphone behaviour, battery expectations and safe use without borrowing claims from similar UGREEN products.
- BLUETOOTH 5.2 • 3.5MM + RCA KIT • TX/RX
- SKU 35223
- Bluetooth 5.2 AUX/RCA Adapter
- Black
- TX + RX
What it does well.
Key features
What it does. a rechargeable Bluetooth 5.2 transmitter/receiver with a 3.5mm port and a cable kit for AUX and stereo RCA equipment.
Audio direction. TX accepts analogue audio from a 3.5mm or RCA source and sends it to Bluetooth headphones/speakers. RX receives Bluetooth audio from a phone/tablet and supplies 3.5mm or stereo RCA analogue output to a car, amplifier or powered speaker.
Codec boundary. No codec list is asserted. Bluetooth 5.2 does not prove aptX, LDAC, AAC or LC3, so none is promised.
Compatibility boundary. 3.5mm AUX and stereo RCA outputs/inputs through the included leads; Bluetooth headphones, earbuds, speakers, phones and tablets. Single 3.5mm aircraft sockets can be used; dual-prong aircraft sockets require the proper adapter and airline permission.
Audio direction: source → product → listener
TX accepts analogue audio from a 3.5mm or RCA source and sends it to Bluetooth headphones/speakers. RX receives Bluetooth audio from a phone/tablet and supplies 3.5mm or stereo RCA analogue output to a car, amplifier or powered speaker.
Why direction matters: transmitter, receiver and headset roles are not interchangeable. A Bluetooth version number also does not establish microphone return, codec, multipoint or low latency.
Before pairing: identify the wired input/output, set the correct operating mode and lower volume at every powered endpoint.
Sound, codecs and latency
Codec support. No codec list is asserted. Bluetooth 5.2 does not prove aptX, LDAC, AAC or LC3, so none is promised.
Delay and sync. No millisecond figure is verified. Suitability for video depends on the complete source-adapter-headphone chain; musical instruments are expressly not recommended.
Real-world sound. Final fidelity depends on the source file, negotiated codec, RF conditions, transducers, fit, amplifier and volume. “Bluetooth 5.x” alone is not a sound-quality tier.
For games and video. Treat every millisecond figure as a controlled test result. Wireless display processing, game engines and headset buffering can add delay.
Use scenarios
Scenario 1. TV or PC analogue output to one or two Bluetooth headphones.
Scenario 2. Single-jack aircraft screen to supported Bluetooth headphones.
Scenario 3. Phone audio to an older car or amplifier via AUX.
Scenario 4. Phone audio to a stereo amplifier through included 3.5mm-to-RCA lead.
Scenario 5. Two-phone RX pairing with one active stream at a time.
Setup and usability guidance
Best practice: pair one endpoint first, verify stable audio, then add any supported second endpoint. This makes faults easier to isolate.
Controls. TX/RX switch, pairing multifunction button, volume/track buttons and built-in microphone are shown. Volume/track controls are for supported RX use, not TX source control.
Microphone and calls. Built-in microphone supports calls in RX mode only. TX does not carry a wireless-headset microphone back through the 3.5mm/RCA source connection.
Two-device behaviour. Dual pairing is supported in TX and RX. TX can share one programme with two headphones; RX connects two source devices but does not mix them. Volume buttons do not work in TX according to official guidance.
Reset path. Forget the adapter on source devices and clear its saved pairings using the manual sequence. Power off before changing direction or re-cabling.
- Step 1: Charge through USB-C and select TX or RX before turning on.
- Step 2: Connect the appropriate included lead to an output in TX or an input in RX.
- Step 3: Enter pairing and connect the first Bluetooth endpoint.
- Step 4: Re-enter pairing for the second endpoint using the manual’s TX or RX sequence.
- Step 5: Keep volume low, then verify which device owns playback or call control.
Compatible devices and systems
Compatibility class: 3.5mm AUX and stereo RCA outputs/inputs through the included leads; Bluetooth headphones, earbuds, speakers, phones and tablets. Single 3.5mm aircraft sockets can be used; dual-prong aircraft sockets require the proper adapter and airline permission.
- Match Bluetooth audio capability, not just the word Bluetooth. Some TVs, consoles and computers support controllers or data but not Bluetooth audio.
- Confirm whether the desired direction is sending audio, receiving audio or returning a microphone. These are separate capabilities.
- Confirm physical connector role and audio type: analogue AUX, optical PCM or USB audio are not interchangeable.
- Update the host operating system and test with other saved Bluetooth devices temporarily disconnected.
- When using branded earbuds/headphones, check their pairing limits and supported codec list too.
What this product does
- Switches between Bluetooth transmitter and receiver roles.
- Uses the documented wired audio interface as input in TX and output in RX.
- Supports the dual-pair and call behaviour stated above.
- Runs from its rechargeable battery for portable use.
- Reconnects to saved devices when mode and endpoint are available.
What this product does not do
- not optical; not USB audio; not a digital RCA S/PDIF adapter; not recommended for musical instruments; TX volume buttons and microphone return are not supported.
- Does not guarantee uninterrupted wireless service through walls, crowds, RF congestion or defective device ports.
- Does not improve a poor recording, repair a damaged socket or guarantee a particular listening volume.
- Does not mix two independent programmes or create independent listener volume unless expressly documented.
- Does not prove compatibility merely because a connector fits or a device advertises Bluetooth.
What to do
Start with one device. Pair and test one endpoint before adding a supported second device or extra cable path.
Keep volume low. Begin at low source and destination volume, especially after switching RX/TX, ANC modes or audio outputs.
Keep firmware and OS current. Updates can improve Bluetooth stability, but use only official vendor updates and do not assume they add unlisted hardware features.
Protect ports and batteries. Grip connectors by housings, keep charging contacts dry and store the product away from loose metal objects.
Confirm active codec or mode. Use the host menu or product display when available. Marketing names do not prove what was negotiated.
Dry before charging. After sweat or a splash, wipe and air-dry completely before returning earbuds to a case or connecting USB power.
What not to do
Do not assume version = feature. Bluetooth 5.x does not automatically mean aptX, LDAC, ANC, multipoint or microphone return.
Do not force connectors. Stop if a plug does not align or fully seat; check direction, port type, case clearance and debris.
Do not charge wet hardware. Moisture plus charging contacts can cause corrosion, heat or failure.
Do not use ANC as protection. Noise cancellation does not certify safe exposure in factories, workshops, shooting, aviation or other hazardous noise.
Do not pair while driving. Configure calls, volume and source switching only while safely parked.
Do not invent reset gestures. Use this model manual; similar HiTune and Bluetooth adapters use different button timing.
Battery, charging and realistic runtime
Runtime: Official model detail separates up to 27 hours TX and 22 hours RX from the 300mAh battery. Real runtime varies with volume, range, call time and temperature.
Power method: USB-C charging. The product is battery powered; the USB-C port is not described as a computer USB audio interface.
- Published runtime is normally measured under controlled conditions; high volume, ANC, premium codecs, calls, displays, cold weather and weak signal can shorten it.
- Lithium batteries age. Lower runtime after repeated cycles is normal; swelling, leakage, excessive heat or odour is not.
- Use compliant cables and power sources, keep ventilation clear and disconnect if the product becomes unusually hot.
- For long storage, avoid leaving the battery empty for months; recharge periodically according to the supplied manual.
Warnings and limitations
- Hearing: start at low volume, take listening breaks and reduce level if you notice discomfort or ringing. ANC is not hearing protection.
- Situational awareness: do not use isolating audio or ANC where hearing traffic, alarms, announcements or instructions is important.
- Battery: do not crush, puncture, burn, short, disassemble or charge a wet/swollen/hot product. Stop use if odour, leakage or deformation appears.
- Children and pets: keep earbuds, tips, adapters and cables away from small children; small components can be a choking hazard.
- Aircraft: follow crew instructions, use only permitted seat audio sockets and keep wireless functions off whenever required.
- Driving: pair and adjust while parked. Hands-free capability does not remove attention or legal obligations.
- Connections: use only low-level headphone/AUX or stated optical/USB interfaces. Do not connect analogue audio ports to mains, speaker-level or unknown industrial signals.
Troubleshooting and reset
No pairing. Move endpoints close together, charge/power both, disconnect competing saved devices, verify TX/RX direction and restart pairing.
Audio but no microphone. Confirm RX mode and the built-in-microphone call path; TX mode does not return a headset microphone.
Drop-outs. Reduce distance, remove body/metal obstruction, move away from crowded 2.4GHz sources and test one paired device at a time.
Delay. Use a low-latency mode only where listed, confirm both endpoints support the needed codec and compare with a wired path.
Only one side/listener. Test the first endpoint alone, then pair the second using the model-specific dual-pair sequence.
Model-specific reset. Forget the adapter on source devices and clear its saved pairings using the manual sequence. Power off before changing direction or re-cabling.
At a glance.
- Product
- UGREEN Bluetooth 5.2 transmitter/receiver kit
- SKU / colour
- 35223 / black
- Bluetooth version
- 5.2
- Audio interface
- 3.5mm analogue; stereo RCA through included cable
- Wireless roles
- TX and RX
- Dual pairing
- Supported in TX and RX
- Microphone
- Built in; RX calls only
- Battery
- 300mAh listed
- Runtime
- Up to 27h TX / 22h RX
- Listed range
- Up to 10m / 32.8ft open conditions
- Charging
- USB-C
- Codecs
- Not specified; no aptX/LDAC inference
- TX control limitation
- Volume buttons do not work in TX
- In the box
- Confirm SKU on the product/box rather than buying by family name alone.
Confirm transmitter versus receiver direction and every wired connector.
Confirm microphone/call need, desired codec and simultaneous-device need separately.
Check whether the source device supports Bluetooth audio, not only Bluetooth peripherals.
Inspect the sealed package on arrival and retain the manual for the correct reset and control map.
Numbers are model listing or exact-media figures unless marked unverified. They are qualified laboratory maxima, not universal guarantees.
Questions buyers ask.
What exactly is UGREEN 35223?
It is a rechargeable Bluetooth 5.2 transmitter/receiver with a 3.5mm port and a cable kit for AUX and stereo RCA equipment.
What is the difference between TX and RX mode?
TX accepts analogue audio from a 3.5mm or RCA source and sends it to Bluetooth headphones/speakers. RX receives Bluetooth audio from a phone/tablet and supplies 3.5mm or stereo RCA analogue output to a car, amplifier or powered speaker.
Which codecs are supported?
No codec list is asserted. Bluetooth 5.2 does not prove aptX, LDAC, AAC or LC3, so none is promised.
Is there a guaranteed low-latency mode?
No millisecond figure is verified. Suitability for video depends on the complete source-adapter-headphone chain; musical instruments are expressly not recommended.
Do calls and the microphone work?
Built-in microphone supports calls in RX mode only. TX does not carry a wireless-headset microphone back through the 3.5mm/RCA source connection.
Can TX or RX mode use two Bluetooth devices at once?
Dual pairing is supported in TX and RX. TX can share one programme with two headphones; RX connects two source devices but does not mix them. Volume buttons do not work in TX according to official guidance.
What battery life should I expect?
Official model detail separates up to 27 hours TX and 22 hours RX from the 300mAh battery. Real runtime varies with volume, range, call time and temperature.
How is it charged or powered?
USB-C charging. The product is battery powered; the USB-C port is not described as a computer USB audio interface.
Which devices are compatible?
3.5mm AUX and stereo RCA outputs/inputs through the included leads; Bluetooth headphones, earbuds, speakers, phones and tablets. Single 3.5mm aircraft sockets can be used; dual-prong aircraft sockets require the proper adapter and airline permission.
What should I do if pairing fails?
Forget the adapter on source devices and clear its saved pairings using the manual sequence. Power off before changing direction or re-cabling.