KPREPUBLIC GK21S
KPREPUBLIC GK21S Mechanical Keyboard Numpad Kit User Manual
Modell: GK21S
1. Einleitung
This manual provides detailed instructions for the KPREPUBLIC GK21S Mechanical Keyboard Numpad Kit. It covers setup, operation, maintenance, troubleshooting, and product specifications to ensure optimal performance and user experience.
The GK21S is a hot-swappable, dual-mode (wired USB Type-C and Bluetooth 5.1) 21-key mechanical numpad kit featuring RGB lighting, custom macro programming, and compatibility with various MX-style switches.
2. Lieferumfang
Upon unboxing your KPREPUBLIC GK21S kit, please verify that all components are present:
- GK21S PCB (Printed Circuit Board)
- Keyboard Case (White)
- USB-Typ-C-Kabel
- Tastenkappenabzieher
- (Note: Keycaps and mechanical switches are not included and must be purchased separately.)
3. Installationsanleitung
3.1 Installing Mechanical Switches
The GK21S features hot-swappable Kailh connectors, allowing for easy installation and removal of mechanical switches without soldering. Ensure your switches are compatible with MX-style sockets (3-pin or 5-pin).
- Align the pins of the mechanical switch with the corresponding holes on the PCB.
- Gently push the switch straight down until it clicks into place. Do not force the switch if it does not align easily, as this may bend the pins.
- Repeat for all 21 switch positions.

Image: The GK21S numpad kit showing the hot-swappable sockets ready for switch installation. The illuminated RGB LEDs indicate power is supplied to the PCB.
3.2 Installing Keycaps
Once switches are installed, place your desired keycaps onto the switch stems. Ensure they are firmly seated.
3.3 Connecting the Numpad
The GK21S supports dual-mode connectivity: wired USB Type-C and Bluetooth 5.1.
3.3.1 Kabelverbindung
- Locate the USB Type-C port on the numpad.
- Connect one end of the provided USB Type-C cable to the numpad and the other end to an available USB port on your computer or device.
- The numpad will be automatically recognized and ready for use.

Bild: Eine detaillierte view of the GK21S numpad's side, highlighting the USB Type-C interface for wired connection.
3.3.2 Bluetooth-Verbindung
The GK21S can connect to up to three Bluetooth devices simultaneously.
- Ensure the numpad is powered on.
- Press the designated key combination (refer to the software manual for specific key bindings, typically Fn + 1, 2, or 3) to enter Bluetooth pairing mode for the desired profile. The RGB lighting may indicate pairing status.
- On your device (laptop, desktop, mobile), navigate to Bluetooth settings and search for new devices.
- Select "GK21S" or a similar name from the list of available devices to pair.
- Repeat for additional devices using different Bluetooth profiles (e.g., Fn + 2 for device 2, Fn + 3 for device 3).
- To switch between connected Bluetooth devices, press the corresponding key combination (e.g., Fn + 1, Fn + 2, or Fn + 3).

Image: The GK21S numpad illustrating its Bluetooth 5.0 dual-mode capability, allowing simultaneous connection and easy switching between up to three devices.
4. Bedienungsanleitung
4.1 Basic Numpad Functionality
The GK21S functions as a standard 21-key numpad for data entry and calculations. Its compact design makes it ideal for users requiring a dedicated numeric input device.
4.2 Anpassungssoftware
The GK21S supports comprehensive customization through its dedicated driver software. This software allows you to:
- Customize all key functions.
- Program custom macros.
- Manage and apply various RGB lighting effects.
- Download and update light effects.
- Define up to three layers of key configurations.
Please refer to the software's built-in help or the manufacturer's website for detailed instructions on using the customization software.

Image: A visual representation of the GK21S driver software, demonstrating its capabilities for key remapping, macro creation, and extensive RGB lighting control.
4.3 RGB-Beleuchtungssteuerung
The numpad features 16.8 million colors RGB SMD switch LEDs. Lighting effects can be controlled and customized via the driver software. The numpad also supports music rhythm and sound control for dynamic lighting effects.
4.4 Umschaltung zwischen zwei Betriebsmodi
To switch between wired and Bluetooth modes, use the designated switch or key combination on the numpad. This allows seamless transition between desktop and mobile use.
5. Wartung
Proper maintenance ensures the longevity and performance of your GK21S numpad.
5.1 Reinigung
- Allgemeine Reinigung: Mit einem weichen, fusselfreien Tuch leichtampened with water or a mild cleaning solution to wipe the case. Avoid harsh chemicals.
- Tastenkappenreinigung: Remove keycaps using the provided keycap puller. Clean them with warm soapy water, rinse thoroughly, and ensure they are completely dry before reattaching.
- Unter Tastenkappen: Use compressed air to remove dust and debris from between the switches and PCB.
5.2 Austausch des Schalters
Thanks to the hot-swappable design, individual switches can be replaced if they malfunction or if you wish to try different switch types. Use a switch puller (not included) to carefully remove the switch, then insert a new one, ensuring pins are aligned.
6. Fehlerbehebung
If you encounter issues with your GK21S numpad, refer to the following common problems and solutions:
| Problem | Mögliche Ursache | Lösung |
|---|---|---|
| Numpad not responding (Wired) | Wackelkontakt, defekter USB-Anschluss, Treiberproblem. | Ensure USB Type-C cable is securely connected. Try a different USB port or cable. Restart your computer. Check device manager for driver issues. |
| Numpad not connecting (Bluetooth) | Numpad not in pairing mode, device Bluetooth off, interference, low battery. | Ensure numpad is in pairing mode (refer to section 3.3.2). Verify Bluetooth is enabled on your device. Charge the numpad battery. Try re-pairing. |
| Schlüssel werden nicht registriert | Switch not fully seated, faulty switch, software conflict. | Press down firmly on the keycap to ensure the switch is fully seated. If issue persists, remove and re-insert the switch. If still problematic, replace the switch. Check customization software for remapped keys. |
| RGB-Beleuchtung funktioniert nicht oder fehlerhaft | Softwareeinstellungen, Firmwareproblem. | Check RGB settings in the customization software. Ensure the software is up to date. Try resetting the numpad (refer to software manual for reset procedure). |
| Akku lädt nicht oder hält die Ladung nicht | Faulty cable, USB port, or battery. | Try a different USB Type-C cable and USB port. Ensure the numpad is connected to a powered USB port. If the issue persists, the battery may need service. |
7. Spezifikationen
Detailed technical specifications for the KPREPUBLIC GK21S Mechanical Keyboard Numpad Kit:
| Besonderheit | Detail |
|---|---|
| Modell | GK21S |
| Schlüssel | 21-key Numpad |
| Konnektivität | Dual Mode: USB Type-C Wired & Bluetooth 5.1 |
| Hot-Swappable Sockets | Yes, Kailh connectors (compatible with Cherry, BOX, G axis, 3-pin/5-pin MX switches) |
| MCU | 32-Bit MCU |
| Flash-Speicher | Built-in 8M Flash |
| RGB-Beleuchtung | 16.8 Million Colors, SMD Switch LEDs, Music Rhythm & Sound Control |
| Anpassung | Driver software for custom macro programming, key remapping, 3 definable layers, light effect customization. |
| Stabilisatoren | PCB support plate mount stabilizer |
| Batterie | 750mAH Li-Battery |
| Kompatible Geräte | Laptops, Desktops, Mobile Devices |
| Material | Acrylnitril-Butadien-Styrol (ABS) |
| Artikelgewicht | 8 Unzen (ca. 227 Gramm) |
| Verpackungsabmessungen | 3 x 3 x 3 Zoll |
| Hersteller | KPREPUBLIC |

Abbildung: Ein interner view of the GK21S PCB, detailing key components such as the 32-bit MCU, 8M Flash memory, and the Bluetooth 5.1 module, which contribute to its advanced functionality.
8. Garantie und Support
For warranty information, technical support, or service inquiries regarding your KPREPUBLIC GK21S Mechanical Keyboard Numpad Kit, please refer to the warranty card included with your purchase or visit the official KPREPUBLIC website. Support resources, including driver downloads and FAQs, are typically available on the manufacturer's product support pages.
Hersteller: KPREPUBLIC
WebWebsite: Please refer to your product packaging or search online for the official KPREPUBLIC support webWebsite.