From the developer: "Reject those unwanted calls such as 'UNKNOWN', 'ANONYMOUS' or user defined names and numbers with Active CallerID. Active CallerID is a Windows-compatible application that monitors the telephone line and processes incoming calls using your voice compatible modem and the Caller ID service that is provided by your local telephone company. Active CallerID has a user-friendly interface that displays the name and telephone number from which the call originated, the time the call was placed, and the date on which it was placed. Active CallerID has a phone Index, call reject capability, a user define translate feature and allows the you to perform a database search from a list of previous callers by name, number or display a list of all caller information that Active CallerID has received."