Check the setting of answering method on your cell phone and confirm if need some setting when connecting the Bluetooth device.

What should I do if the computer says they need a driver or transmitter to connect the earbuds?

Here are some methods for your reference.·Download a Bluetooth receiver to connect(in the computer settings)·Kindly check if your computer’s Bluetooth version supports Bluetooth 5.0

How to adjust the volume by earbuds?

Long press L or R earbud to adjust the volume while playing music.# R earbud Volume +# L earbud Volume -The volume adjustment is not available when it`s connected to a TV and computer.

NC9 Pro Hybrid Active Noise Cancelling Wireless Earbuds-TOZO

Support TOZO APP： Through the connection with the TOZO app, the headset will be used more effectively and conveniently. TOZO APP offers quick and easy access to Active Noise Cancellation mode and EQ mode switch, as well as the ability to save noise reduction intensity customized adjustment and EQ curve settings. It can be used to customize Gesture operations and perform OTA software updates on the product. Where you can become acquainted clearly with the Quick Guide and Product FAQ.
Advanced Bluetooth 5.3： Advanced Bluetooth 5.3 technology that's compatible with devices with Bluetooth audio capability, Pick up the two headsets from the charging case, and they will be paired automatically. Then simply enable Bluetooth connection on your mobile phone to pair the device with your earbuds.
Transparent Mode： You can hear what you want to hear, which lets outside sound in so you can hear and interact with the world around you. You can clearly hear the announcement of the airline or subway and what is happening around you without taking off the headphones.
Active Noise Cancellation： Hybrid 3-layer Active Noise Cancellation. 1. Outward-facing microphone detects external sounds and counter with equal anti-noise to first cancel noise. 2. Inward-facing microphone listens inside the ear canal to pick up internal sounds and produce anti-noise again to cancel the left noise. 3. Ear caps prevent 90% of noise from going to the ear canal.
Call Noise Cancellation： TOZO NC9 Pro supports Call Noise Cancellation. which means that when the Bluetooth headset is used for a call, the chip inside the Bluetooth headset is used to filter the signal received by the call microphone to reduce the wind noise from the outside world so that the caller can hear it more clearly.

Support TOZO APP： Through the connection with the TOZO app, the headset will be used more effectively and conveniently. TOZO APP offers quick and easy access to Active Noise Cancellation mode and EQ mode switch, as well as the ability to save noise reduction intensity customized adjustment and EQ curve settings. It can be used to customize Gesture operations and perform OTA software updates on the product. Where you can become acquainted clearly with the Quick Guide and Product FAQ.
Advanced Bluetooth 5.3： Advanced Bluetooth 5.3 technology that's compatible with devices with Bluetooth audio capability, Pick up the two headsets from the charging case, and they will be paired automatically. Then simply enable Bluetooth connection on your mobile phone to pair the device with your earbuds.
Transparent Mode： You can hear what you want to hear, which lets outside sound in so you can hear and interact with the world around you. You can clearly hear the announcement of the airline or subway and what is happening around you without taking off the headphones.
Active Noise Cancellation： Hybrid 3-layer Active Noise Cancellation. 1. Outward-facing microphone detects external sounds and counter with equal anti-noise to first cancel noise. 2. Inward-facing microphone listens inside the ear canal to pick up internal sounds and produce anti-noise again to cancel the left noise. 3. Ear caps prevent 90% of noise from going to the ear canal.
Call Noise Cancellation： TOZO NC9 Pro supports Call Noise Cancellation. which means that when the Bluetooth headset is used for a call, the chip inside the Bluetooth headset is used to filter the signal received by the call microphone to reduce the wind noise from the outside world so that the caller can hear it more clearly.