Internet & Phone Working Together with Filters

When you have CenturyLink® High-Speed Internet and telephone service on the same line, you need to use filters. DSL filters separate the incoming signal, so you can be online and still use your phone, DVR and other devices.

When devices aren't connected to a filter, or filters are installed incorrectly, you can experience:

  • Static or a hissing sound on your telephone line
  • Slow Internet speeds
  • Intermittent connection to the Internet
  • No connection to the Internet

What devices need a filter?

Every device that connects to your phone line -- except your modem -- needs a DSL filter. For example:

  • Telephones, caller ID units, answering machines
  • Satellite TV receivers, cable boxes, DVRs, TiVos
  • Fax machines
  • Security systems
  • Automatic water meters
IMPORTANT: DON'T connect a filter to your modem.
Devices that need filters
These common household devices need filters.

If you have a multi-line phone system or a home security system, contact us. Chances are that you had a "whole home" filter installed during your service visit, or you might want to discuss having one installed with an agent.

Let's install some filters!

You should have received 2 inline filters from CenturyLink already. (They came in the installation kit with your modem.)

Inline filters are plugged in between your jack and your device. To install one, plug it into a wall jack, and then plug a phone cord or other device into the other end.

Need filters? Chat with us to order more, or purchase them from an electronics store.

Other kinds of filters & how to get them

A wall-mount filter can be used for wall-mounted phones that an inline filter can't fit behind. You can chat with us to request wall mount filters, or purchase them at an electronics store.

If your modem (Motorola or 2Wire) has only 1 jack, use an inline adapter

The adapter connects to the wall jack and has 2 ports:

  1. Use the one labeled -- "To Modem" or "DSL/HPNA" -- to connect your modem.
  2. Use this one labeled -- "Phone -- to connect your telephone or other device.

Chat with us to order an inline adapter, or purchase one at your local electronics store. 


If you have filters installed correctly and are still having trouble, visit the Phone Guidance Center or Internet Guidance Center for more help.