CenturyLink C4000XG Gigabit Fiber WiFi Modem Router User Manual

1. Introduction and Overview

The CenturyLink C4000XG is a high-performance Gigabit Fiber WiFi Modem Router designed to provide robust internet connectivity for your home or business. This device integrates a fiber modem with a Wi-Fi 6 router, offering advanced features for a seamless online experience. It supports fiber speeds up to 2.5 Gbps download and 1 Gbps upload, making it suitable for demanding internet usage.

Figure 1: Front view of the CenturyLink C4000XG Modem Router. This image displays the sleek, cylindrical design of the device with a prominent status LED on the front.

2. Key Features

• Wi-Fi 6 (802.11ax) Antenna: Supports both 2.4 GHz and 5 GHz bands, backward compatible with 802.11a/b/g/n/ac standards, providing high-speed wireless connectivity.
• Gigabit Fiber Support: Capable of handling fiber internet speeds up to 2.5 Gbps download and 1 Gbps upload.
• Dynamic QoS (Quality of Service): Prioritizes internet traffic based on application and device, ensuring smoother streaming, gaming, and browsing.
• Multiple Gigabit Ports: Features 5 Gigabit Ethernet ports (1 WAN + 4 LAN) for reliable wired connections.
• Smart Connect: Intelligently selects the fastest Wi-Fi band (2.4 GHz or 5 GHz) for each connected device, optimizing performance with a single wireless network name (SSID).
• Intel Wi-Fi 6 Gig+: Incorporates next-generation Wi-Fi technology for enhanced performance in connected homes.
• Enhanced Security: Provides security features for your home or business network and all connected devices.

3. What's in the Box

Upon unboxing your CenturyLink C4000XG Modem Router, please ensure all the following components are present:

• CenturyLink C4000XG Modem Router Unit
• Power Adapter
• Ethernet Cable
• Quick Start Guide

4. Setup and Installation

Follow these steps to set up your CenturyLink C4000XG Modem Router:

1. Identify Ports and Buttons: Familiarize yourself with the various ports and buttons on your C4000XG device. Refer to Figure 2 for a detailed diagram.


Figure 2: Detailed diagram of the CenturyLink C4000XG showing top, front, back, and bottom views with labeled components including Top Vent, Status LED, WPS Button, USB 2.0 Port, WAN & LAN Ports, Power port, Reset Button, and Credential Label.

2. Connect the Fiber Optic Cable: If your service uses a direct fiber connection, carefully connect the fiber optic cable from your wall outlet to the designated fiber port on the modem. Ensure the connection is secure but do not force it.
3. Connect the Power Adapter: Plug the power adapter into the 'Power' port on the back of the C4000XG and then into a standard electrical outlet.
4. Power On: The device will automatically power on. Wait for the Status LED on the front of the modem to turn solid green, indicating a successful connection to the CenturyLink network. This may take several minutes.
5. Connect Your Devices:
   • Wired Connection: Use the provided Ethernet cable to connect your computer or other network device to any of the 'LAN' ports on the back of the C4000XG.
   • Wireless Connection: Locate the Wi-Fi network name (SSID) and password on the label usually found on the bottom or back of the C4000XG (refer to Figure 2, Credential Label). Select this network on your wireless device (smartphone, laptop, tablet) and enter the password to connect.
6. Access the Admin Interface (Optional): For advanced settings, open a web browser on a connected device and type the default gateway IP address (usually 192.168.0.1 or 192.168.1.1) into the address bar. Log in using the default username and password found on the device label.

5. Operating Instructions

Once your CenturyLink C4000XG is set up, it will automatically manage your internet connection. Here are some operational aspects:

• Wi-Fi Connectivity: The C4000XG utilizes Smart Connect, meaning it broadcasts a single Wi-Fi network name (SSID) and intelligently directs your devices to the optimal 2.4 GHz or 5 GHz band for the best performance.
• WPS (Wi-Fi Protected Setup): For quick and easy connection of WPS-compatible devices, press the 'WPS Button' on the front of the modem (refer to Figure 2). Then, activate WPS on your device within two minutes.
• Dynamic QoS: This feature automatically prioritizes network traffic, ensuring that bandwidth-intensive activities like video streaming or online gaming receive preference for a smoother experience. No user configuration is typically required for basic QoS operation.
• Status LED: The LED on the front of the device indicates its operational status. A solid green light typically means the modem is connected to the internet and functioning correctly. Consult the Quick Start Guide for detailed LED status meanings.

6. Maintenance

To ensure optimal performance and longevity of your CenturyLink C4000XG Modem Router, consider the following maintenance tips:

• Placement: Place the modem in a central location in your home, away from obstructions, large metal objects, and other electronic devices that may cause interference. Ensure adequate ventilation around the device; do not block the top vent (refer to Figure 2).
• Cleaning: Gently wipe the exterior of the device with a soft, dry cloth. Do not use liquid cleaners or abrasive materials.
• Rebooting: Periodically rebooting your modem (by unplugging the power adapter for 30 seconds and then plugging it back in) can resolve minor connectivity issues and improve performance.
• Firmware Updates: CenturyLink typically manages firmware updates automatically. Ensure your device remains connected to the internet to receive these updates, which can improve security and performance.

7. Troubleshooting

If you encounter issues with your CenturyLink C4000XG, try the following troubleshooting steps:

• No Internet Connection:
  • Check all cable connections (power, Ethernet, fiber) to ensure they are secure.
  • Observe the Status LED on the front of the modem. If it's not solid green, there might be an issue with your internet service.
  • Reboot the modem by unplugging the power adapter for 30 seconds, then plugging it back in. Wait a few minutes for it to reconnect.
• Slow Wi-Fi or Frequent Disconnections:
  • Ensure the modem is placed in an open, central location, away from interference sources.
  • Check if too many devices are simultaneously using high-bandwidth applications.
  • Try rebooting the modem.
• Cannot Access Admin Interface:
  • Ensure your device is connected to the C4000XG network (wired or wireless).
  • Verify you are typing the correct IP address (e.g., 192.168.0.1) and login credentials.
  • Clear your browser's cache and cookies, or try a different browser.
• Factory Reset: If all else fails, you may perform a factory reset. This will erase all custom settings and restore the modem to its original factory defaults.
  • With the modem powered on, use a paperclip or a similar pointed object to press and hold the 'Reset Button' (refer to Figure 2) for approximately 10-15 seconds until the Status LED flashes.
  • Release the button and wait for the modem to restart. You will need to reconfigure your Wi-Fi settings and any other custom settings after a factory reset.

8. Specifications

9. Warranty and Support

This CenturyLink C4000XG Modem Router is offered as an Amazon Renewed product. Please note the following regarding support and warranty:

• Amazon Renewed Guarantee: As a renewed product, it is eligible for replacement or refund under the Amazon Renewed Guarantee if you are not satisfied with your purchase. This typically includes a 90-day return policy. For specific details regarding your purchase, please refer to the Amazon Renewed terms and conditions or your order details.
• Technical Support: For technical issues related to the functionality of the CenturyLink C4000XG modem router, such as internet connectivity problems or advanced configuration, it is recommended to contact CenturyLink customer support.
• Product Condition Support: For issues related to the "renewed" condition of the product, such as physical defects or performance not matching "like new" standards, please contact Amazon Renewed support or the seller from whom you purchased the device.