PhoneTray Pro requires a voice/data/fax modem with caller id support in order to monitor incoming calls and block unwanted callers. You will need a voice modem in addition to the DSL, cable or wireless modem that you use to access the internet.
If you do not have a voice modem, you can purchase PhoneTray Pro + Modem package or buy one of the modems listed below. All modems listed here have been tested and work well with PhoneTray Pro.
Note: If you have Comcast XFINITY please purchase a Sewell modem or Hiro H50228 modem (one of the first two modems listed above).