A configurable PSTN call-handling (CPC) service enables monitoring and custom responses to calls received over multiple subscriber lines associated with a user. A CPC Client Program runs on a computer and presents a graphical user interface (GUI) that allows the user to associate call-handling options with call characteristics, such as caller, date, or time. The GUI also allows the user to customize the notification signals provided and to provide custom responses to certain callers, by associating call characteristics with various GUI appearances, sound files, or images. The CPC relieves the communications network of performing certain call-handling functions, such as call forwarding, by moving decision-making processes to the user's PC. The user can remotely monitor any subscriber line associated with the user from any browser, because the communications network sends notifications directly to an IP address specified by the user, rather than to the IP address associated with the subscriber line.