CM721 USB-C audio and charging adapter · signal-path guide

UGREEN USB-C Audio + 60W Charging Adapter (25837)

UGREEN USB-C Audio + 60W Charging Adapter (25837), model CM721, lets a compatible USB-C phone, tablet, laptop or handheld send digital audio to a 3.5mm analog headset/speaker while receiving USB-C charging power through the adapter’s separate female USB-C port.

Overview

The built-in DAC is listed up to 32bit/384kHz and the charging path up to 60W. These are different paths: the 3.5mm port handles analog audio, while the female USB-C port accepts charging input only.

The USB-C charging receptacle does not carry data, storage, video, a USB hub or a second USB-C audio accessory. The adapter is not a wall charger, and 60W requires a compatible external charger, cable and receiving device.

Performance and planning

Headline watts and gigabits are negotiated maximums, not universal results. Plan around every device, port, cable, charger, battery state and protocol in the path.

The DAC ceiling describes supported PCM conversion, not a promise that every phone, app, operating system or track will output 32bit/384kHz. The host audio stack, source file, application settings and connected analog equipment determine the actual format and audible result.

The charging path is pass-through. The adapter draws operating power and the receiving device negotiates with the external charger, so device-side power may be lower than the charger’s printed 60W or the adapter ceiling.

A 60W-capable USB-C charger and cable do not force 60W. Phones normally request far less; some laptops may require more than 60W or may not accept charging through an audio adapter.

Listening while charging can reveal noise from a poor-quality charger, earth loop, vehicle AUX system or sensitive earphones. Test audio without the charger, then add a standards-compliant charger to isolate the source.

The product page explicitly says no data transfer. The USB-C female port cannot connect storage, a keyboard, an Ethernet adapter or a monitor.

Setup and usability guidance

Use this sequence for a controlled first connection. Follow the connected-device maker’s stricter instruction whenever it differs.

1. Confirm the host has USB-C and supports digital USB audio accessories. A USB-C receptacle alone does not guarantee audio support.
2. With charging disconnected, insert the adapter’s USB-C male plug fully into the host device.
3. Connect a compatible 3.5mm headset, headphone cable, powered speaker or AUX lead to the clearly marked audio port.
4. Select the USB audio output in the operating system or application if it does not switch automatically, then test at low volume.
5. For simultaneous charging, connect a standards-compliant USB-C charger to the adapter’s female USB-C charging port using a suitable cable.
6. Confirm stable audio and charging, then raise volume gradually. Grip connector housings when disconnecting; do not pull or separate the magnetic section under load.

What this product does

These are the supported functions of this product when the complete connection is compatible.

• Converts compatible digital USB-C audio into analog 3.5mm output through its DAC.
• Supports listed PCM decoding up to 32bit/384kHz when the host and software provide it.
• Accepts external USB-C charging input and passes negotiated power to the connected host up to 60W.
• Allows compatible audio and charging to operate at the same time.
• Can carry compatible headset microphone/call functions through the 3.5mm path.

What to do

These habits support reliable charging, data, audio and battery use while reducing avoidable connector strain.

• Verify digital USB audio support on the host device.
• Connect and test audio before adding charging power.
• Begin at low volume, especially with sensitive in-ear monitors.
• Use a standards-compliant charger and cable for pass-through charging.
• Route the short adapter without hanging the weight of a long AUX cable or charger lead from the device port.
• Keep the marked audio and charging ports distinct.

Warnings and limitations

Review these electrical, thermal, transport and physical limits before connecting valuable equipment.

• Stop using the product if a connector, cable jacket, battery enclosure or plug is bent, cracked, loose, swollen, scorched or unusually hot.
• Keep connectors dry and free of lint or metal debris. Disconnect power before cleaning; never probe a port with metal.
• Never modify, splice, crush or tightly knot a charging cable, charger or battery pack.
• Start at low volume. High sound levels can damage hearing; the adapter’s “Hi-Res” label is not a safe-volume guarantee.
• The magnetic design is not MagSafe, Qi, a medical-safe breakaway or a data connector. Keep it away from magnetic-stripe cards and magnet-sensitive devices.
• Some combinations can produce hum while charging. Disconnect charging immediately if noise is severe, heat appears or the charger/cable is unverified.
• Vehicle use must not obstruct pedals, steering, gear selection, airbags or driver attention.
• Microphone, calls and inline controls depend on headset wiring, application and host support; test before relying on them.

Package contents

Only components supported by the model record or an official model package list are included here. Scene devices and props are excluded.

• 1 × UGREEN CM721 USB-C audio + charging adapter, SKU 25837.
• A USB-C wall charger, USB-C charging cable, headphones, 3.5mm AUX cable, phone, tablet and laptop are not identified as included.

Care and troubleshooting

Disconnect power before inspection and change one variable at a time when diagnosing a connection.

• Disconnect the charger, host and 3.5mm accessory before cleaning. Use a dry, lint-free cloth and keep liquid out of every receptacle.
• Store the adapter without a sharp fold beside either strain relief and keep the magnetic section free of metal debris.
• If there is no audio, confirm the host supports USB audio, select the USB audio output, reconnect at low volume and test another compatible headset.
• If the microphone fails, test the headset directly or with another known CTIA adapter and verify the application input setting.
• If charging is slow, remove other adapters, verify charger/cable profiles and compare the host’s supported input. Remember that the adapter ceiling is 60W.
• If hum appears only while charging, disconnect power, test a reputable charger/cable and isolate vehicle or speaker ground-loop causes before continued use.
• Replace the adapter if the braided lead frays, the magnetic housing loosens, ports wobble or abnormal heat develops.