PINTs and SPIRITS - service interworking

These two IETF standards address the requirement for telephony services to interwork between the PSTN and the Internet. PINT deals with services originating from an IP network; SPIRITS deals with services originating from the PSTN.

In PINT (PSTN and Internet Interworking), PSTN network services are triggered by IP requests. A SIP Java client is embedded in a Java servlet on a web server. The SIP client then launches requests to create phone calls on the telephone network. Being a lightweight client that is embedded in many devices, SIP is the ideal choice for the IP portion of signalling. It partners with INAP on the PSTN side.

The current focus of this initiative is to allow web access to voice content and enable click-to-dial/fax services. For more information, see the PINT charter

The SPIRITS (Service in the PSTN/IN Requesting Internet Service) initiative also addresses IP-PSTN cross-signalling environments but this time IP network services originate from PSTN/IN requests. The benchmark services for SPIRITS are: Internet call-waiting, Internet caller-ID delivery and Internet call-forwarding. For example, a CO switch detects that you are online and when a call comes from the PSTN, it gateways the call over the IP network and notifies you that you have a call waiting. You can then accept the call, reject the call or send the call to voicemail.

The SPIRITS charter provides more details.