Troubleshooting your modem, starting with the cords

The first and most basic step of troubleshooting problems with your internet service is how your modem is setup.

Inspect the cords and cables going to your modem

Start by making sure the modem is plugged in and turned on. The light on the front of the modem labeled POWER should be lit up. You should also check that the other cables or cords are securely inserted at both ends. If you're not sure, then unplug the cord or cable and plug it back in. When you hear it CLICK, you know you've inserted it correctly.

Check all the cords and cables to make sure they are in good and working condition. Look for bends, kinks or cuts. If you find a bad one or if you're not sure, then replace it and see if that solves the problem.

Is everything plugged into the correct port or outlet?

The most basic modem setup looks like this:

  1. The power cord (or AC Adapter) goes from the wall electrical outlet to the modem outlet labeled POWER.
  2. A regular phone cord goes from the wall phone jack directly to the modem outlet labeled DSL or LINE (label varies by modem), and in most modems this outlet is color-coded green.
  • There is a green phone cord included in the modem kit you received from CenturyLink.
  • You don't have to use the green phone cord, any phone cord is sufficient.
  • Although it's a phone cord, it doesn't actually go into the modem outlet labeled PHONE.

It's best to connect your computer directly to the modem whenever you're troubleshooting your internet service. This helps rule out wireless connection problems. It also of course adds another connection to your modem set-up.

Common modem setup situations known to cause problems

Make sure you avoid these common setup mistakes that are known to cause problems with an Internet connection.

  • Don't use a DSL filter between the wall phone jack and the modem.
    The modem already has a built in filter, so it's important that you DON'T use an in-line filter from your telephone wall jack to the modem. This is the only line where you don't want to use a filter. Putting a filter on this line will prevent the data signal from reaching the modem and consequently preventing a connection to the Internet.

  • Don't connect the modem's phone cord to phone splitters or phone jacks built into surge protectors.
    The phone cord connecting the wall phone jack to the modem DSL or LINE port should be direct without any other type of equipment in between the two.
  • Don't connect from the wall phone jack to the modem port labeled PHONE.
    The phone cord that runs between the wall jack and the modem should go into the modem port labeled DSL or LINE (label varies by modem). The PHONE port on the modem is intended for connecting to a telephone device.

How to properly connect a landline phone through the same wall phone jack as the modem

If you have plain old telephone service through CenturyLink, then you might find you want to also attach a telephone, fax or answering machine to the same phone jack as your modem.

No problem! With the proper setup, you can avoid causing inadvertent problems with your internet connection.

Adding a phone

If you only need to connect one phone device, then the proper setup is to run a phone cord from the modem port labeled PHONE to your telephone, fax machine, or answering machine.

This allows all of signal to go directly into the modem and then the modem acts as a filter and sends the voice signal through the modem's phone port. It's almost magic!

What about two phone devices?

If you want to connect a phone and another telephone type device, connect a regular phone splitter to the phone port on the modem. Then connect your devices to the splitter. The goal here is to put the splitter at the modem PHONE outlet and not the wall jack.

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Troubleshoot problems with your phone or internet service