service in the PSTN/IN requesting Internet service (IP/IETF) (SPIRITS)

The SPIRITS protocol transfers teleservices from the PSTN to IP networks in intelligent networks( IN). These IETF activities are described in RFC 3136 as Informational.

It is functionally equivalent to the PINT protocol, PSTN to InternetInternetworking (PINT), except that it operates in the opposite direction. Essentially, it is service features for telephony such as callforwarding, call forwarding, call pickup, caller ID, etc. Spirits could be used to trigger actions on the Internet from circuit-switched networks, for example.