UGREEN 30445 CM123 Bluetooth 5.0 AUX/RCA Receiver
UGREEN 30445 CM123 Bluetooth 5.0 AUX/RCA Receiver
Overview

Key features
Role
a compact Bluetooth 5.0 music receiver for adding wireless playback to an amplifier, powered speaker, stereo, soundbar or car audio system with 3.5mm or left/right RCA input.
Audio path
A phone, tablet or computer sends Bluetooth music to CM123. The receiver outputs analogue stereo through 3.5mm and/or its red/white RCA jacks. It does not send television audio to Bluetooth headphones.
Codec boundary
The Bluetooth 5.0 evidence lists A2DP and EDR but does not publish a dependable codec list. SBC/AAC, aptX, LDAC and lossless Bluetooth are therefore not promised.
Power design
Up to 8 hours playback is listed. Runtime is a laboratory maximum and changes with volume, battery age, temperature and radio conditions. Micro-USB power/charging, about 2 hours to full. The receiver can be used while powered, but a noisy USB supply may introduce audible interference.
Audio direction and connector roles
A phone, tablet or computer sends Bluetooth music to CM123. The receiver outputs analogue stereo through 3.5mm and/or its red/white RCA jacks. It does not send television 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
The Bluetooth 5.0 evidence lists A2DP and EDR but does not publish a dependable codec list. SBC/AAC, aptX, LDAC and lossless Bluetooth are therefore not promised.
Latency
No low-latency codec or millisecond result is for this revision. Use a wired connection where lip-sync or instrument monitoring is critical.
Microphone and calls
No microphone or call-return path is documented. Treat SKU 30445 as a music receiver, not a speakerphone or computer headset adapter.
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
Modernising an older amplifier with RCA inputs.
Scenario 2
Adding Bluetooth to powered desktop speakers through 3.5mm.
Scenario 3
Feeding two compatible line inputs from the two analogue output formats.
Scenario 4
Temporary car AUX playback where the receiver can be charged safely.
Scenario 5
Using while powered for longer home listening.

Setup and usability guidance
- Step 1: Charge or power CM123.
- Step 2: Connect 3.5mm or RCA output to a line/AUX input; an RCA cable is not listed in the box.
- Step 3: Select the matching input and begin with low amplifier volume.
- Step 4: Hold the multifunction button as documented, then choose the receiver in the source Bluetooth menu.
- Step 5: Play a test track and raise volume gradually; test each wired output separately before using both.
Usability rule: establish one clean path first. Add a second source, listener, output or peripheral only after the first works reliably.
Controls
A multifunction button and status LEDs manage power and pairing. Volume remains primarily controlled by the source and connected audio system.
Second-device behaviour
media verifies that the 3.5mm and RCA outputs can feed two compatible audio inputs/speaker systems at the same time. It does not verify two-phone Bluetooth multipoint.
Recovery
Forget CM123/UGREEN on the source, disconnect any competing saved source, power-cycle the receiver and re-pair within one metre. Follow only the CM123 button timing.

Compatible devices and systems
Class: Bluetooth music sources including compatible phones, tablets and computers; analogue destinations with 3.5mm AUX or left/right RCA line input.
- 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 microphone, calls, Bluetooth-headphone transmission, optical/coaxial audio, multipoint or published codec guarantee; RCA is line-level, not passive-speaker power.
- 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: Up to 8 hours playback is listed. Runtime is a laboratory maximum and changes with volume, battery age, temperature and radio conditions.
Charging/connection: Micro-USB power/charging, about 2 hours to full. The receiver can be used while powered, but a noisy USB supply may introduce audible interference.
- 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
No microphone or call-return path is documented. Treat SKU 30445 as a music receiver, not a speakerphone or computer headset adapter. 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
Forget CM123/UGREEN on the source, disconnect any competing saved source, power-cycle the receiver and re-pair within one metre. Follow only the CM123 button timing.
Technical specifications
| Product / model | UGREEN Hi-Fi Bluetooth receiver / CM123 |
|---|---|
| SKU / colour | 30445 / black |
| Bluetooth version | 5.0 + EDR, stored revision |
| Wireless role | Receiver only |
| Profiles/evidence | A2DP listed; codec list not published |
| Audio outputs | 3.5mm stereo and left/right RCA |
| Output use | Outputs may be used individually or together |
| Frequency response | 20Hz–22kHz |
| Listed SNR / load | 90dB; RL=16Ω |
| Runtime | Up to 8 hours |
| Charging | Micro-USB, about 2 hours; use while powered |
| Listed range | Up to 10m / 33ft in open conditions |
| Dimensions | 66.6 × 66.6 × 24mm listed |
Listed ranges and runtimes are qualified maxima in suitable conditions, not universal guarantees.
Package contents
Package: CM123 receiver, Micro-USB charging cable, 1m 3.5mm audio cable and manual; an RCA cable and charger are not listed.
Pre-purchase checklist
- 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.
Product-specific FAQ
What exactly is UGREEN 30445?
It is a compact Bluetooth 5.0 music receiver for adding wireless playback to an amplifier, powered speaker, stereo, soundbar or car audio system with 3.5mm or left/right RCA input.
What does this receiver connect to?
A phone, tablet or computer sends Bluetooth music to CM123. The receiver outputs analogue stereo through 3.5mm and/or its red/white RCA jacks. It does not send television audio to Bluetooth headphones.
Which codecs does SKU 30445 support?
The Bluetooth 5.0 evidence lists A2DP and EDR but does not publish a dependable codec list. SBC/AAC, aptX, LDAC and lossless Bluetooth are therefore not promised.
Is low latency guaranteed?
No low-latency codec or millisecond result is for this revision. Use a wired connection where lip-sync or instrument monitoring is critical.
Do microphone and calls work?
No microphone or call-return path is documented. Treat SKU 30445 as a music receiver, not a speakerphone or computer headset adapter.
Can two phones or outputs be used?
media verifies that the 3.5mm and RCA outputs can feed two compatible audio inputs/speaker systems at the same time. It does not verify two-phone Bluetooth multipoint.
What battery life or power does it use?
Up to 8 hours playback is listed. Runtime is a laboratory maximum and changes with volume, battery age, temperature and radio conditions. Micro-USB power/charging, about 2 hours to full. The receiver can be used while powered, but a noisy USB supply may introduce audible interference.
Which devices and systems are compatible?
Bluetooth music sources including compatible phones, tablets and computers; analogue destinations with 3.5mm AUX or left/right RCA line input.
What should I do if pairing fails?
Forget CM123/UGREEN on the source, disconnect any competing saved source, power-cycle the receiver and re-pair within one metre. Follow only the CM123 button timing.
What is in the package?
CM123 receiver, Micro-USB charging cable, 1m 3.5mm audio cable and manual; an RCA cable and charger are not listed
What should it not be used for?
receiver only; no microphone, calls, Bluetooth-headphone transmission, optical/coaxial audio, multipoint or published codec guarantee; RCA is line-level, not passive-speaker power.