1. Introduction
This manual provides instructions for the installation, operation, and maintenance of your ZYXEL P660HN-51R ADSL/ADSL2+ Wi-Fi Router. This device integrates a DSL modem, a router, and a Wi-Fi access point into a single unit, designed for ADSL-based internet connections.

Figure 1: ZYXEL P660HN-51R functioning as a 3-in-1 device (DSL Modem, Router, and Wi-Fi AP).
2. Safety Information
- Ensure the device is placed on a stable, flat surface.
- Do not expose the device to water or excessive humidity.
- Avoid placing the device near heat sources or in direct sunlight.
- Use only the power adapter provided with the device.
- Do not open the device casing; refer servicing to qualified personnel.
- Ensure adequate ventilation around the device to prevent overheating.
3. Package Contents
Verify that your package contains the following items:
- ZYXEL P660HN-51R ADSL/ADSL2+ Wi-Fi Router
- Power Adapter
- Ethernet Cable
- DSL Phone Cable
- Setup Wizard and auto-detect software (typically pre-loaded or on a CD/download)
- Quick Start Guide (not explicitly mentioned but implied)
4. Product Overview
The ZYXEL P660HN-51R is a compact device designed for efficient internet connectivity. It features various ports and indicators for easy setup and monitoring.

Figure 2: Front view of the ZYXEL P660HN-51R ADSL/ADSL2+ Wi-Fi Router.
Front Panel Indicators
- Power LED: Indicates power status.
- Ethernet LEDs: Indicate activity on the LAN ports.
- DSL LED: Indicates DSL line synchronization status.
- Internet LED: Indicates internet connection status.
- WLAN/WPS Button/LED: Indicates Wi-Fi status and initiates WPS pairing.

Figure 3: Rear view of the ZYXEL P660HN-51R showing ports and connections.
Rear Panel Ports
- Power Input: Connects to the power adapter.
- Reset Button: Used to restore factory default settings.
- Ethernet Ports (LAN 1-4): Connect wired devices like computers or gaming consoles.
- DSL Port: Connects to the telephone line for ADSL service.
5. Setup Instructions
Follow these steps to set up your ZYXEL P660HN-51R router.
5.1. Hardware Connection
- Connect one end of the DSL phone cable to the DSL port on the router and the other end to your telephone wall jack.
- Connect one end of the Ethernet cable to any of the LAN ports (1-4) on the router and the other end to your computer's Ethernet port.
- Connect the power adapter to the router's power input and then plug it into a power outlet.
- Press the Power button (if available) to turn on the device.
5.2. Initial Configuration
The ZYXEL P660HN-51R includes a built-in setup wizard and an auto-detect feature to simplify the configuration process.

Figure 4: Easy setup with the integrated wizard and auto-DSL detection.
- Open a web browser on the connected computer.
- The setup wizard should automatically launch. If not, type the default IP address (usually 192.168.1.1 or 192.168.0.1) into the browser's address bar and press Enter. Refer to the label on the bottom of your device for the exact IP address and login credentials.
- Follow the on-screen instructions provided by the setup wizard. The auto-detect feature will attempt to configure your DSL settings automatically.
- You may need to enter your Internet Service Provider (ISP) username and password if prompted.
- Once the setup is complete, the Internet LED on the front panel should turn solid green, indicating a successful connection.
5.3. Compatibility Notes
This product is designed to work with ADSL, ADSL2, and ADSL2+ internet services. It is compatible with most ADSL-based internet connections provided by various ISPs.

Figure 5: The ZYXEL P660HN-51R is compatible with ADSL2+, ADSL2, and ADSL services.
Important: This device is not compatible with VDSL, Cable, FiOS, Satellite, or bonded ADSL internet services. If you are unsure about your service type, contact your ISP for verification before proceeding.
6. Operating Instructions
6.1. Wired Connections
To connect devices via Ethernet:
- Use standard Ethernet cables to connect your computers, gaming consoles, or other network devices to the LAN ports (1-4) on the rear of the router.
- The corresponding Ethernet LED on the front panel will illuminate when a connection is established and blink during data activity.
6.2. Wireless Connections (Wi-Fi)
The router provides 802.11n Wi-Fi connectivity.
- Connecting via WPS: Press the WLAN/WPS button on the front panel of the router. Within two minutes, press the WPS button on your Wi-Fi device (e.g., laptop, smartphone). The devices will automatically connect.
- Connecting Manually:
- On your Wi-Fi device, search for available wireless networks.
- Select the network name (SSID) of your ZYXEL router (usually found on a label on the device).
- Enter the Wi-Fi password (WPA/WPA2 key), also found on the device label.
- Your device should now be connected to the Wi-Fi network.
7. Maintenance
- Cleaning: Use a soft, dry cloth to clean the exterior of the device. Do not use liquid cleaners or aerosols.
- Firmware Updates: Periodically check the ZYXEL support website for firmware updates to ensure optimal performance and security.
- Restarting: If you experience connectivity issues, try restarting the router by unplugging the power adapter for 10 seconds and then plugging it back in.
- Factory Reset: To restore the router to its factory default settings, press and hold the Reset button on the rear panel for approximately 10 seconds using a paperclip or similar pointed object. This will erase all custom configurations.
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No Power LED indication. | Power adapter not connected or faulty. | Ensure power adapter is securely connected to the router and a working power outlet. Try a different outlet. |
| DSL LED is off or blinking. | No DSL signal or synchronization issue. | Check DSL cable connection. Ensure your service is active. Contact your ISP if the issue persists. |
| Internet LED is off or red. | No internet connection or configuration error. | Verify DSL LED is solid. Re-run the setup wizard. Confirm ISP username/password. Contact your ISP. |
| Cannot connect to Wi-Fi. | Incorrect Wi-Fi password or Wi-Fi disabled. | Ensure correct SSID and password. Check WLAN/WPS LED. Restart the router. |
| Slow internet speed. | Interference, network congestion, or ISP issue. | Move router away from interference sources. Limit simultaneous downloads. Contact your ISP. |
| Router not compatible with my service. | Service type is not ADSL, ADSL2, or ADSL2+. | This router only supports ADSL-based services. It is not compatible with VDSL, Cable, Fiber, or bonded ADSL. Confirm your service type with your ISP. |
9. Specifications
| Brand | ZYXEL |
| Model Name | P660HN-51 |
| Item Model Number | 91-004-981026B |
| Wireless Type | 802.11n |
| Frequency Band Class | Single-Band |
| Connectivity Technology | Wireless, Ethernet (4-port switch) |
| Compatible Devices | Personal Computer, Wi-Fi enabled devices |
| Recommended Uses | Home Internet Connectivity |
| Operating System | ZYXEL's proprietary OS |
| Item Weight | 1.6 pounds (approx. 0.73 kg) |
| Product Dimensions (LxWxH) | 1.57 x 5.2 x 3.46 inches (approx. 4 x 13.2 x 8.8 cm) |
| Voltage | 12 Volts (DC) |
| Special Feature | WPS (Wi-Fi Protected Setup) |
| Antenna Type | Internal |
10. Warranty & Support
10.1. Warranty Information
For detailed warranty information, please refer to the warranty card included with your product or visit the official ZYXEL website. Standard manufacturer warranty terms and conditions apply.
10.2. Technical Support
If you encounter issues that cannot be resolved using this manual, please visit the ZYXEL support website for FAQs, firmware downloads, and contact information for technical assistance.
Official ZYXEL Website: www.zyxel.com





