PRESENCE INFORMATION METHOD AND SYSTEM

摘要

A method of operating an availability service in a telecommunication system (1) interconnecting a legacy telephone system (10) with at least one presence system (11), said legacy telephone system including a plurality of terminals (T1...T10), at least some (T1,T2) of which are terminals of subscribers to said availability service, said method including: (a) continuously monitoring each subscriber terminal (T1,T2) for a change of a call status of said subscriber terminal from the presence of a call to the absence of a call; (b) generating a first or "high availability" signal when said call status o f said subscriber terminal changes from said presence of a call into said absence of a call; (c) monitoring an interval of time beginning with said first signal; (d) generating a second or "availability unknown" signal after a predetermin ed time period .tau.within said interval; and (e) making said availability signals accessible to any interconnected presen ce system.