C4000 modem setup

This page provides instructions to self-install internet with any C4000 series modem/router.

C4000 front & rear view

For the following models:
Greenwave C4000BG  *  C4000LG  *  C4000XG  *  Zyxel C4000LZ

Not the right kind of modem? Try the tower modem setup page instead.

Have you ordered new internet service or a new Greenwave C4000 or Zyxel C4000LZ modem from CenturyLink, and are setting up the service yourself? There are some things you need to know before completing the self-install process. For the best results, read the full instructions below before you begin.

First, your modem will arrive in the mail on or before the date your service is scheduled to start. Look for an email with your order confirmation details and an order status tracking link. Your line should be activated no later than 7 p.m. on your start date. You may receive a notification earlier in the day to let you know that your service has been activated, and then you can start your installation. If in doubt, you may want to wait until 7 p.m. to hook up your modem.

Start by unpacking the box and identifying the modem, cables, and instruction card. If needed, you can download the same instructions below.

What's in the box?

  • Modem 
  • Power cord (black)
  • Ethernet cables (yellow and white)
  • DSL cable (green) - Does not come with the C4000XG model

We suggest using the My CenturyLink app on your iOS or Android device to complete modem setup. The app makes installing your modem a snap, and is also a great way to manage all your CenturyLink services. But, if you don't want the app, no problem — you can use a web browser on your computer to complete installation. Just follow the QuickConnect instructions when you get to step 4.

Next, you'll need to find a good spot for your modem. Where it is placed can have a huge impact on your wireless performance. 

  • Find a central location in your house, avoiding closets or other closed-off areas to ensure that all devices in your home get a strong wireless signal from the router.
  • Choose a spot with good air circulation that doesn't get hot, as excessive heat can cause electronics to perform poorly.

Now it's time to get your modem hooked up.

  1. Plug the black power cord into a wall outlet and into the power port on the back of the modem. 
  1. For the C4000BG or LG/LZ, plug one end of the green cord into the green DSL port on back of the modem, and the other end into a working phone jack. Note that the C4000XG does not have a DSL port. 
C4000 DSL port and power

DSL and power ports on the back of the C4000BG and LG/LZ models

  1. Finally, plug one end of the yellow Ethernet cord into one of the Ethernet ports on the modem, and the other end into your computer's Ethernet port. 

No Ethernet port? If you are using a tablet or newer laptop, you may not have an Ethernet port on your device. That's okay. If your device doesn't have Ethernet, you can instead connect to WiFi using the login information on the bottom of the modem.

C4000 bottom label

If you see a white cord in your modem kit, it's a second Ethernet cable to be used in case you have additional devices that you would like to plug into the modem.

Do you have both internet and home phone service from CenturyLink?

If NO, proceed to step 3.

If you have the C4000BG or LG/LZ model and you have both landline phone service (not VOIP) and high-speed internet, you will need to install DSL filters on all of your phone cords. These are essential to make sure you get the best phone and internet connection. See the detailed instructions and diagrams below.

Filters are not needed if you use the C4000XG

Phone plugging into filter (diagram)

Plug the phone cord into a filter and then into the wall jack

Note: If you have cordless phones, you only need to install a filter on the phone base that plugs in to the wall jack; no filters are needed on the cordless units that only plug into an electrical outlet.

Do not install a filter between the modem and the wall jack.

Modem plugging in with no filter (diagram)

The DSL cord from the modem to the jack should not have a filter

As an alternative, use a splitter to plug both a phone and a DSL modem into one wall jack.

Phone and modem plugging into DSL splitter (diagram)

Use a DSL splitter to plug a phone and a modem into one wall jack

Have a home security system? Chat with customer service to get a technician to install a whole-home filter on the line outside your home (there is an installation fee for this.)

Filters are not included in your modem kit. If you have a landline phone and internet with CenturyLink, filters should have been included at the time of your order and will arrive in a separate package. If you did not receive filters, please chat with us.

C4000 status light

The single status light ring on the front of the C4000 looks different from older modem models with separate lights for Internet, DSL, Ethernet, WiFi, etc. But the function is basically the same. The status light ring will change colors as it goes through the installation process, to show you its connection status. 

While the C4000 initially boots up, it will blink blue while it is looking for the CenturyLink network. It should turn solid BLUE once it has connected. 

Troubleshooting tip: If the light blinks blue, check to make sure the green DSL cord is firmly plugged in to both the modem and the wall jack. If it blinks blue again for more than 5 minutes, service is not connected to that jack. Please try another jack or chat with us for further help.

The C4000BG and LG/LZ models also have one or two DSL status lights beneath the ports on the back side, as seen in the photo. These lights will flash red and green while the modem is syncing. The C4000XG does not have a DSL port or light.

  • Once the status light ring on the front turns blue, the DSL light(s) should then turn green to indicate it's connected and ready to finish setting up.
C4000LG rear ports and DSL display light

If the DSL light turns GREEN

This means your modem is connected to our network and the line is active. You can continue to step 4 to compete setup.

If the DSL light turns RED

This means the network is not being detected by your modem. This may happen for one of these reasons:

  • The CenturyLink network hasn't yet been connected at your address. Some people call on their service start date to say their modem isn't working, when often the issue is simply that the service hasn't been activated. If you're having connectivity issues, try waiting until after 5 p.m. to attempt setup.
  • The particular jack you are using isn't hooked up or is faulty. Try plugging the green cord into a different jack. 


If the DSL light remains red after checking the cords and trying all available jacks, you will need to chat with a service agent to get help.

If the DSL light is OFF

This indicates nothing is connected to the modem port. Check to make sure the green cord is firmly plugged in to the wall jack and into the DSL port on the modem.

After plugging in your modem, it may take up to 15 minutes for the equipment to install updates and establish a connection with the network.

At this point, you are ready to activate your service! You can proceed using the mobile app or the QuickConnect site on a browser — either one will walk you through the steps to finish installing service. 

Option 1: In the My CenturyLink mobile app, go into the Install my New Modem section. 

Option 2: Open a browser on your computer and go to http://connect.centurylink.com (not "https"). Follow the steps to complete the installation process using QuickConnect. And don't worry — if your computer is connected to the modem, you will be able to access this site even before your internet service is fully activated.

After completing the setup steps in the app or through the QuickConnect site, check the color of the light ring on the front of the modem to verify its connection status.

C4000 status light

The light ring turns GREEN

Once the light is green, you're connected to the internet and you can get online!

The light ring turns AMBER

If the light is amber/orange, this means the setup process is not yet complete or you have not yet accepted the user agreement. Use the My CenturyLink mobile app or browse to http://connect.centurylink.com, and follow the prompts to finish setup.

The light ring turns RED

This means a connection failure has occurred. Try disconnecting everything (DSL and power), waiting a few minutes, and repeating steps 2 through 4. If you still get a red light, you will need to chat with an agent to get further troubleshooting help.

For full instructions on how to read the single status light on the C4000 modem, visit our detailed guide.

Below are some of the most common questions and issues that customers ask as they self-install a modem.

What if all the lights on the modem are off?

It may sound obvious, but if none of the lights are coming on, it most often means something isn't fully plugged in.
Try this:

  • Make sure the power cord is fully and firmly plugged in on both ends: into the power port on the modem and into the wall outlet.
  • Make sure the outlet is live. You can test this by plugging in another electrical device, and/or try another outlet.

What if the DSL light is red?

Only the C4000BG and LG/LZ models have a DSL light. The red light indicates the modem isn't connecting to the CenturyLink network. This can be either because the service hasn't been activated yet, you're using an inactive jack, or there's an issue with the modem's authentication process.
Try this:

  • Check your order confirmation to make sure you've got the right date that your service is scheduled to start. 
  • Wait until after 7 p.m. on the service start date to attempt setup.
  • Try another phone jack if one is available. 
  • Try rebooting the modem. Unplug everything, wait a few minutes, and plug in again. This can often resolve a connection issue.
  • As a last resort, you can try using the reset button.

How long should the setup process take?

This can depend on a number of factors. The initial boot-up process can take up to 15 minutes as the modem updates firmware and syncs with the network. The remaining setup will depend on your installation method (using the My CenturyLink app or the QuickConnect site) and how quickly you go through the steps. 

Can I use any jack in my home?

This can depend on the age of your home. In an older home, there may be multiple jacks, and they may have been installed by different providers over the years. It may be that only one of the jacks is hooked up to CenturyLink's network, or all of them may be active.

If you have questions we haven't answered, or if you need any additional support with setting up your modem, chat with us. We're here to help!

Was this page helpful?