A telephone service method that provides subscribers with the functionality of an extra telephone line during data/Internet sessions. Each subscriber has a unique telephone number Dns that can be dialed by anyone with access to the PSTN. When the Dns is dialed the call will be routed via the PSTN to the ILTD server. The ILTD server upon receiving the call attempt from the Dnc will analyze the dialed number (Dns) and determine if the subscriber's computer is able to receive the telephone call. If the subscriber's computer is actively engaged in an Internet Protocol session, with the ILTD client software running, the ILTD server will connect the call over the Internet to the ILTD client software. The ILTD client software will activate the subscriber's sound card and the microphone to play audio and receive input from the microphone to allow the subscriber and the calling party to have a full duplex telephone conversation (i.e. using voice-over-IP technology).