Product Overview
The AVANTEK CB-21 Wireless Doorbell system provides a reliable and convenient solution for your home or office. It features a long wireless range, multiple melodies, adjustable volume levels, and a durable, waterproof design.

Image: The AVANTEK CB-21 Wireless Doorbell kit, showing one plug-in receiver and two wireless push-button transmitters.
Key features include:
- 1,000 FT/300 M Long Wireless Range: Ensures you never miss a visitor, even if you are a few rooms away or on another floor.
- 52 Melodies & 5 Volume Levels: Tailor your doorbell experience with a wide selection of tunes and adjustable volume up to 115 dB.
- IP55 Dustproof and Waterproof: The transmitter is designed to withstand various harsh weather conditions, operating between -4 °F to 140 °F.
- Memory Function: Remembers your last melody and volume level after a power outage, eliminating the need to reset settings.
- Easy Installation: Can be fixed to the wall using included screws and anchors or double-sided adhesive pads.
- Long Battery Life: The transmitter uses a lithium battery with a 3-year maximum lifespan.
Setup and Installation
Follow these steps to set up your AVANTEK Wireless Doorbell:
- Unpack Components: Ensure all components are present: 1 plug-in receiver, 2 transmitters, 2 adhesive tapes, 1 screwdriver, 4 screws, and 4 anchors.
- Receiver Placement: Plug the receiver into a standard electrical outlet in a central location within your home.
- Transmitter Battery Activation: Before mounting the transmitter, open its casing to remove the battery insulating strip. This activates the pre-installed lithium battery.

Image: Illustration demonstrating the process of opening the transmitter to remove the battery insulating strip, which is crucial for initial power-up.
- Mounting the Transmitter: Choose one of the following methods:
- Solution A (Adhesive Tape): Clean the mounting surface thoroughly. Peel off one side of the double-sided adhesive tape and stick it to the back of the transmitter. Peel off the other side and firmly press the transmitter onto the desired location (e.g., door frame or wall) for at least 30 seconds.
- Solution B (Screws and Anchors): Use the provided screws and anchors for a more secure installation. Mark the desired drilling points, drill pilot holes, insert the anchors, and then screw the transmitter into place.

Image: Visual guide for installing the doorbell transmitter using either double-sided adhesive or screws and anchors.
Operating Instructions
The AVANTEK Wireless Doorbell is designed for simple operation:
- Changing Melodies:
The receiver offers 52 different melodies. To cycle through them, press the "Music Selection" button on the side of the receiver. Press the button repeatedly until you find your desired tune.

Image: The doorbell receiver highlighting its features: 52 selectable chimes and tunes, 5 adjustable volume levels, and an LED indicator for visual alerts.
- Adjusting Volume:
There are 5 adjustable volume levels, with a maximum setting of 115 dB. Press the "Volume Control" button on the side of the receiver to increase or decrease the volume to your preference.
- Pairing Transmitters (Custom Tones):
You can set a different ring tone for each transmitter, allowing you to distinguish which doorbell has been rung (e.g., front door vs. back door). To do this:
- Select your desired melody on the receiver.
- Press and hold the "Volume Control" button on the receiver for approximately 5 seconds until the LED indicator flashes rapidly. This indicates pairing mode.
- Immediately press the button on the transmitter you wish to pair with this melody. The receiver will chime once to confirm successful pairing.
- Repeat for other transmitters with different melodies if desired.

Image: Demonstrates how different ring tones can be assigned to individual transmitters, allowing users to differentiate between multiple entry points.
- Memory Function:
The doorbell system is equipped with a memory function. In case of a power outage, your last selected melody and volume level will be remembered, and you will not need to reset them.
Maintenance
- Battery Replacement (Transmitter):
The transmitter uses a CR2032 lithium battery with an average lifespan of 3 years. When the transmitter's LED indicator no longer flashes or the range decreases significantly, it's time to replace the battery.
- Carefully open the transmitter casing using a small flat-head screwdriver or the provided tool by inserting it into the small notch on the side and gently prying it open.
- Locate the coin cell battery (CR2032).
- Gently pry out the old battery.
- Insert a new CR2032 battery with the positive (+) side facing up.
- Snap the transmitter casing back together securely.
- Cleaning:
Wipe the doorbell receiver and transmitter with a soft, dry cloth. Do not use abrasive cleaners or solvents, as these may damage the finish or internal components. The transmitter is IP55 dustproof and waterproof, but avoid submerging it in water.

Image: The doorbell transmitter shown in a wet environment, illustrating its IP55 dustproof and waterproof capabilities, suitable for outdoor use.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Doorbell does not ring. |
|
|
| Short wireless range. |
|
|
| Receiver LED flashes but no sound. | Volume is set to mute (0 dB). | Press the "Volume Control" button to increase the volume. |
Product Specifications
| Feature | Detail |
|---|---|
| Model Number | CB-21 |
| Wireless Range | 1,000 ft / 300 m (open air) |
| Melodies | 52 |
| Volume Levels | 5 (up to 115 dB) |
| Transmitter Battery | CR2032 Lithium Battery (3V) |
| Receiver Power Source | AC & Battery (Plug-in) |
| Waterproof Rating (Transmitter) | IP55 |
| Operating Temperature | -4 °F to 140 °F (-20 °C to 60 °C) |
| Material | ABS |
| Dimensions (Receiver) | Approx. 2.87 x 0.6 x 3.15 inches |
| Dimensions (Transmitter) | Approx. 1.57 x 0.6 x 3 inches |
| Included Components | 1 Receiver, 2 Transmitters, 2 Adhesive Tapes, 1 Screwdriver, 4 Screws, 4 Anchors, 1 User Manual |

Image: Detailed dimensions of the compact receiver and transmitter units, showing they are designed not to obstruct adjacent power sockets.
Warranty and Support
AVANTEK is committed to delivering top-notch products and customer satisfaction. Our wireless doorbell is approved by FCC, CE, and RoHS standards.
For any inquiries, technical support, or warranty claims, please refer to the official AVANTEK customer service channels. You can also find additional resources and product information by visiting the official AVANTEK store:
A comprehensive User Manual in PDF format is also available for download: Download User Manual (PDF)





