How do I test if my DSL filter is working?

Your phone and Internet use the same line. DSL filters split the signal coming into your home so both your phone and Internet service can share that line. Incorrectly connected and/or damaged DSL filters can cause noise on your line.

  • Confirm that your DSL filters are properly connected. Every electronic device that’s plugged into a phone jack – except your DSL modem – needs a filter. If you only have one wall jack and your phone and DSL modem need to plug into it together, use a DSL dual filter.
  • This includes: cordless phones, satellite receivers, computers (modem or power strip), caller id boxes, fax machines, answering machines and alarm/security systems.

To test your DSL filter and check if you have a problem:

  1. Leave your corded telephone and your modem attached to the phone line.
  2. Disconnect all other devices from their phone jacks.
  3. One at a time, reattach each device and filter to its phone jack and check the phone for noise again after plugging in each device.
  4. If you find that the sound gets bad after reattaching a device, replace that filter.