Introduction
Thank you for choosing the Callez GC500D2 2.5mm Corded Headset. This headset is designed for clear communication and comfort, compatible with a wide range of cordless and landline phones featuring a 2.5mm jack. It also includes an adapter for use with devices that have a single 3.5mm audio jack.
Key features include a noise-cancelling microphone for clear audio, convenient in-line volume and mute controls, and a lightweight, adjustable design for extended wear.
Package Contents
- Callez 2.5mm Corded Headset
- 2.5mm Headset to 3.5mm Jack Adapter
- User Manual
Product Overview

The Callez 2.5mm Corded Headset, featuring an adjustable headband, soft ear cushion, and flexible microphone boom.
The Callez GC500D2 headset is engineered for durability and user comfort. It features a single ear design, allowing you to stay aware of your surroundings while on a call. The microphone boom is flexible and rotatable, enabling precise positioning for optimal voice pickup.
- Adjustable Headband: Ensures a comfortable fit for various head sizes.
- Soft Ear Cushion: Provides comfort during long periods of use.
- Flexible Microphone Boom: Allows for 330° rotation and precise positioning.
- In-line Controls: Easy access to microphone mute and volume adjustments.
Setup and Installation
Connecting to a 2.5mm Cordless/Landline Phone
To connect your headset to a compatible phone, locate the 2.5mm headset jack on your device. This is typically found on the side or bottom of the phone handset or base unit.
- Ensure your phone is powered on.
- Insert the 2.5mm jack of the headset firmly into the headset port on your phone.
- Once connected, you should be able to hear and speak through the headset.

The 2.5mm jack of the headset being plugged into the dedicated headset port on a Panasonic cordless phone.
Connecting to 3.5mm Devices (using adapter)
The included 2.5mm to 3.5mm jack adapter allows you to use your headset with devices such as laptops, desktops, tablets, and smartphones that feature a single 3.5mm audio jack.
- Connect the 2.5mm jack of the headset into the 2.5mm female end of the adapter.
- Insert the 3.5mm jack of the adapter into the 3.5mm audio port on your computer, tablet, or smartphone.
- Adjust audio settings on your device if necessary to select the headset as the input/output device.

The 2.5mm to 3.5mm adapter allows connection to laptops, desktops, tablets, and smartphones with a single 3.5mm audio jack.
Setup Demonstration Video
This video demonstrates the physical features of the headset, including the rotatable microphone and adjustable headband, and shows how to connect the headset to a 2.5mm phone and a laptop using the 3.5mm adapter.
Operating Instructions
In-line Controls
The headset features convenient in-line controls for managing your calls.

Close-up view of the in-line controls, showing the microphone mute switch and volume adjustment slider.
- Microphone Mute Switch: Slide the switch to 'OFF' to mute your microphone. Slide to 'ON' to unmute.
- Volume Control Slider: Slide the control up or down to adjust the listening volume.
Compatibility
The Callez GC500D2 headset is designed for broad compatibility with various communication devices.
2.5mm Jack Compatibility
This headset is compatible with most cordless and landline phones that have a standard 2.5mm headset jack, including models from:
- Panasonic
- Uniden
- VTech
- AT&T
- Cisco SPA
- RCA
- Polycom
- Grandstream
- Cisco Linksys
- Clarity
- Zultys
- Cortelco
- Gigaset
For specific Panasonic models, compatibility includes, but is not limited to: KX-TGF575S, KX-TGF352N, KX-TGA470, KX-TGA652, KX-TGA660, KX-TGA931T, KX-TGA950B, KX-TGE430B, KX-TGE432, KX-TGE433B, KX-TGEA20, KX-TGEA40, KX-TG6592T, KX-NT136, KX-NT343, KX-NT346, KX-NT366, KX-T7603, KX-T7625, KX-T7630, KX-T7633, KX-T7636, KX-T7730, KX-T7735, KX-T7736, KX-TG7731, KX-DT521.

A comprehensive list of compatible phone brands and specific Panasonic models for the 2.5mm headset.
3.5mm Jack Compatibility (with adapter)
Using the included 2.5mm to 3.5mm adapter, the headset is compatible with most smartphones, computers (laptops and desktops), and tablets that have a single 3.5mm audio jack. Please note that it is not compatible with iPhone 7/8/X/XS/XR/11/12/13/14/15/16/17 models.
Features and Comfort
Crystal Clear Calls with Noise-Cancelling Microphone
The headset features a noise-cancelling microphone designed to filter out background noise, ensuring your voice is heard clearly by the person on the other end. This enhances communication quality, especially in busy environments.

An illustration demonstrating how the noise-cancelling microphone reduces background distractions for clearer communication.
Lightweight and All-Day Comfort
Designed for extended use, the headset is super lightweight and features an adjustable headband and soft leatherette ear cushions. This combination ensures a comfortable fit for various head sizes and reduces fatigue during long calls.

Visual representation of the headset's comfort features, including soft ear cushions, an adjustable headband, and a 330° rotatable microphone.
Troubleshooting
If you encounter issues with your Callez GC500D2 headset, please refer to the following common solutions:
- No Sound/Low Volume:
- Ensure the headset's 2.5mm jack (or 3.5mm adapter) is fully and securely plugged into the device.
- Check the in-line volume control on the headset and adjust it to an audible level.
- Verify the volume settings on your phone or computer.
- Microphone Not Working:
- Check the in-line microphone mute switch and ensure it is in the 'ON' (unmuted) position.
- Confirm that the microphone is selected as the input device in your computer's sound settings if using the 3.5mm adapter.
- Ensure the microphone boom is positioned correctly near your mouth.
- Echo or Distorted Audio:
- Reduce the volume on your headset or phone to prevent feedback.
- Ensure all connections are secure.
- Test the headset with another compatible device to rule out device-specific issues.
If these steps do not resolve the issue, please contact customer support.
Specifications
| Model Number | GC500D2 |
| Connectivity Technology | Wired |
| Headphone Jack | 2.5 mm Jack (includes 3.5mm adapter) |
| Ear Placement | On Ear |
| Impedance | 32 Ohms |
| Noise Control | Sound Isolation, Noise Cancellation (Microphone) |
| Additional Features | Adjustable Headband, Lightweight, Microphone Included, Volume Control |
| Material | Leather, Metal, Plastic |
| Color | Black |
Warranty and Support
Callez provides a 45-day return policy for replacement and a 2-year warranty for this product. For any warranty claims or technical support, please contact us directly.
- Warranty Period: 2 years
- Return Policy: 45 days for replacement
- Contact Information: sales@callez.net
Please retain your proof of purchase for warranty service.