Providing internet users with presence information about telephone lines in the public switched telephone network

摘要

Presence state information is made available to an Internet user about a public switched telephone network (PSTN) subscriber utilizing a first terminal that does not have direct Internet communications capability. First messages from the PSTN switch providing communication services to the PSTN subscriber are received. The first messages contain call event information. The presence state of the PSTN subscriber is determined based on the call event information. A second message is transmitted using Internet protocol to the Internet terminal of the Internet user, the second message containing the presence state information about the PSTN subscriber.