UGREEN 70601 CM309 Bluetooth 5.0 Car AUX Receiver
Overview
- Bluetooth 5.0
- SKU 70601
- CM309
- Receiver only
What it does well.
Key features
Role. an integrated USB-powered Bluetooth 5.0 receiver that sends phone music, navigation and supported calls into an existing car or speaker 3.5mm AUX input.
Audio path. A phone, tablet or computer is the Bluetooth source. CM309 receives that audio, passes it through its attached 3.5mm plug and uses the attached USB-A lead only for power. It cannot transmit AUX audio to Bluetooth headphones.
Codec boundary.
Power design. No internal battery. The USB-A plug must remain powered whenever the receiver is in use. USB-A supplies 5V operating power; 3.5mm carries analogue audio. Connecting only one lead is insufficient.
Audio direction and connector roles
A phone, tablet or computer is the Bluetooth source. CM309 receives that audio, passes it through its attached 3.5mm plug and uses the attached USB-A lead only for power. It cannot transmit AUX audio to Bluetooth headphones.
Connector rule: a source/output must feed a destination/input. USB power, USB host data, analogue AUX and Bluetooth radio roles are separate even when one enclosure handles several of them.
Start safely: set the correct mode, select the target input and lower every volume control before testing.
Sound, codecs, calls and latency
Codecs.
Latency. No latency result is verified. It is suitable for ordinary music/navigation reception, not guaranteed lip-sync, gaming or instrument monitoring.
Microphone and calls. The built-in microphone supports hands-free calls. Call clarity depends on mic position, road/vent noise, phone network and car acoustics; it is not active noise cancellation.
Real-world fidelity. Source file, negotiated codec, radio conditions, analogue cable, amplifier and speakers/headphones all affect the result. A newer Bluetooth number is not automatically higher sound quality.
Use scenarios
Scenario 1. Adding phone music to an older car AUX system.
Scenario 2. Playing navigation prompts through car speakers.
Scenario 3. Hands-free calls using the built-in microphone.
Scenario 4. Streaming to an older powered home speaker with USB nearby.
Scenario 5. Automatic use with vehicle USB power after initial pairing.
Setup and usability guidance
Usability rule: establish one clean path first. Add a second source, listener, output or peripheral only after the first works reliably.
Controls. Playback and calls are primarily controlled from the phone. Complete pairing and choose AUX while parked.
Second-device behaviour.
Recovery. Unplug USB power, forget CM309 on the source, reconnect power and pair again within one metre. Keep other saved phones disconnected during recovery.
- Step 1: Connect USB-A to a suitable power port and 3.5mm to the AUX input.
- Step 2: Select AUX on the stereo and start at low volume.
- Step 3: Open the source Bluetooth menu and choose the UGREEN/CM309 receiver.
- Step 4: Play a test track and make a stationary call to check microphone pickup.
- Step 5: If power noise is audible, try a different compliant USB supply or route the cable away from interference.
Compatible devices and systems
Class: Bluetooth music/call sources and car stereos, powered speakers or amplifiers that offer both a 3.5mm AUX input and a suitable USB-A power source.
- Match the operating-system/audio profile and connector role, not only the Bluetooth logo.
- Confirm whether you need programme audio, microphone return, peripheral data or file transfer; these use different profiles.
- For AUX/RCA products, confirm the destination is a line-level input and already has its own amplifier.
- For PC adapters, verify driver requirements and disable a competing built-in Bluetooth radio.
- For two-way products, confirm that the chosen TX or RX mode matches the wired device.
What this product does
- Receives Bluetooth audio from a compatible source.
- Outputs analogue audio to the stated 3.5mm and/or RCA line input.
- Supports only the call, control and source-count behaviour documented for this revision.
- Reconnects to a saved compatible source when powered and available.
- Modernises existing audio equipment without replacing its amplifier or speakers.
What this product does not do
- receiver only; no battery, Bluetooth-headphone transmission, RCA/optical output, multipoint, AAC/aptX/LDAC, USB data audio or water rating; not for cars without AUX.
- Does not guarantee uninterrupted wireless service through metal, walls, crowds or heavy 2.4GHz interference.
- Does not repair a damaged source, USB port, AUX socket, amplifier or speaker.
- Does not make a connector compatible merely because it fits physically.
- Does not prove ANC, aptX, LDAC, multipoint or microphone return from the Bluetooth version number alone.
What to do
Check the label. Confirm SKU, model and stored revision on the product or box before relying on a specification.
Begin with one endpoint. Pair and test one path before adding any supported second device or output.
Lower volume first. Protect hearing and speakers when changing mode, output, codec, call profile or device.
Keep connections dry. Inspect USB and audio plugs, remove debris without metal tools and dry completely before power.
Use official drivers/manuals. Use the CM/BT model instructions; related UGREEN revisions can use different buttons and radios.
Pause before switching. When two sources are connected, pause the current programme before starting the other.
What not to do
Do not infer features. Bluetooth 5.x/6.0 alone does not establish codec, ANC, microphone, multipoint or delay.
Do not force plugs. Stop if a connector does not align; check port type, direction, damage and case clearance.
Do not use speaker-level output. AUX/RCA receiver inputs are line-level; passive speakers still need an amplifier.
Do not pair while moving. Configure car and aircraft audio before movement and follow local/crew instructions.
Do not charge damaged cells. Stop for swelling, leakage, odour or abnormal heat and seek proper battery disposal.
Do not borrow reset timing.
Battery, charging and realistic runtime
Battery/power: No internal battery. The USB-A plug must remain powered whenever the receiver is in use.
Charging/connection: USB-A supplies 5V operating power; 3.5mm carries analogue audio. Connecting only one lead is insufficient.
- Published runtime is normally a controlled maximum; volume, calls, codec, temperature, range and battery age can shorten it.
- USB-powered models have no reserve runtime and stop when vehicle/computer power stops.
- Use compliant, undamaged power sources and disconnect any product that becomes unusually hot.
- Do not leave rechargeable products empty for months; follow the manual for long-term storage.
Warnings and limitations
- Hearing: begin at low volume, limit exposure and stop if you notice discomfort or ringing. Bluetooth features and noise processing are not hearing protection.
- Battery: never crush, puncture, short, burn or charge a swollen, leaking, wet or unusually hot rechargeable product. USB-powered models still require a sound, compliant 5V source.
- Aircraft: follow crew instructions, use only permitted headphone outputs and keep wireless devices off whenever directed. Carry lithium products in accordance with airline rules.
- Driving: pair, mount, select sources and set volume while parked. Hands-free calling does not remove attention or legal responsibilities.
- Water: This product does not has a IP rating. Keep adapters, plugs and charging ports dry; never connect power while damp.
- Heat and storage: do not leave the product on a hot dashboard, near a heater or in direct sun. Keep small adapters and cables away from children and pets.
- Audio ports: connect only to the stated headphone/AUX line-level role. Never connect a 3.5mm/RCA port to mains, passive-speaker output or an unknown industrial signal.
Troubleshooting and reset
No pairing. Bring devices close, verify power/mode, disconnect competing saved devices and pair one endpoint first.
Connected but silent. Check source playback, OS output, TX/RX direction, AUX input selection, cable seating and both volume controls.
Audio but no microphone. The built-in microphone supports hands-free calls. Call clarity depends on mic position, road/vent noise, phone network and car acoustics; it is not active noise cancellation. Confirm the call app input and permissions only where a microphone path is documented.
Drop-outs. Reduce distance and metal/body obstruction, move from crowded 2.4GHz radios and test one connection at a time.
Delay. Compare with a wired path; no unstated codec or Bluetooth version can remove all source and endpoint buffering.
Reset path. Unplug USB power, forget CM309 on the source, reconnect power and pair again within one metre. Keep other saved phones disconnected during recovery.
At a glance.
- Product / model
- UGREEN car Bluetooth audio receiver / CM309
- SKU / colour
- 70601 / grey
- Wireless role
- Receiver only
- Codec
- SBC documented for legacy revision; no others asserted
- Audio connection
- Attached 3.5mm AUX plug
- Power connection
- Attached USB-A, required during use
- Microphone
- Built in for supported calls
- Listed range
- Up to 10m under open conditions
- Cable form
- Coiled lead, compact car layout
- Battery
- None
- Multipoint
- Not for stored revision
- In the box
- Confirm this SKU/revision on the sealed product.
Confirm TX, RX or Windows-host direction.
Confirm every wired input/output and required power source.
Confirm call/microphone, codec and second-device needs separately.
Check whether any cable, charger or flight adapter you require is actually listed.
Listed ranges and runtimes are qualified maxima in suitable conditions, not universal guarantees.
Package: Integrated CM309 USB-A-to-3.5mm Bluetooth receiver and documentation; no charging cable or battery is required.
Questions buyers ask.
What exactly is UGREEN 70601?
It is an integrated USB-powered Bluetooth 5.0 receiver that sends phone music, navigation and supported calls into an existing car or speaker 3.5mm AUX input.
What does this receiver connect to?
A phone, tablet or computer is the Bluetooth source. CM309 receives that audio, passes it through its attached 3.5mm plug and uses the attached USB-A lead only for power. It cannot transmit AUX audio to Bluetooth headphones.
Which codecs does SKU 70601 support?
Is low latency guaranteed?
No latency result is verified. It is suitable for ordinary music/navigation reception, not guaranteed lip-sync, gaming or instrument monitoring.
Do microphone and calls work?
The built-in microphone supports hands-free calls. Call clarity depends on mic position, road/vent noise, phone network and car acoustics; it is not active noise cancellation.
Can two phones or outputs be used?
What battery life or power does it use?
No internal battery. The USB-A plug must remain powered whenever the receiver is in use. USB-A supplies 5V operating power; 3.5mm carries analogue audio. Connecting only one lead is insufficient.
Which devices and systems are compatible?
Bluetooth music/call sources and car stereos, powered speakers or amplifiers that offer both a 3.5mm AUX input and a suitable USB-A power source.
What should I do if pairing fails?
Unplug USB power, forget CM309 on the source, reconnect power and pair again within one metre. Keep other saved phones disconnected during recovery.
What is in the package?
Integrated CM309 USB-A-to-3.5mm Bluetooth receiver and documentation; no charging cable or battery is required
What should it not be used for?
receiver only; no battery, Bluetooth-headphone transmission, RCA/optical output, multipoint, AAC/aptX/LDAC, USB data audio or water rating; not for cars without AUX.