Will NetZero DSL affect my phone service?

No, your NetZero DSL service should not affect your phone service at all. Even though your DSL modem uses your phone line, it makes use of a different signal or channel than the one used by your phone for voice communication. Just plug in the special DSL filters (provided in the Broadband Installation Kit) between your phone and the jack to make sure your regular phone calls don't cause interference with your DSL signal.