Technical specification: Reliable RTT (Real-Time Text)

The technical specification describes a private Session Initiation Protocol (SIP) [IETF RFC 3261] header (P-header), used to achieve real-time sending of text using SIP Message requests, along with its applicability. The formatting of the real-time text (RTT) messages follows ITU-T Recommendation T.140.

This Technical Specification for RTT exchange between ICT systems (including networks, devices, services and protocols) is made available by the Swedish Post and Telecom Authority (PTS), www.pts.se. It is made freely available and without any claims on Intellectual Property Rights (IPRs) providing a common specification for RTT exchange. Its most recent, published version always supersedes all previous versions.

The copyright for this specification belongs to the Swedish Post and Telecom Authority (PTS). This specification is free to use and to publish.

The specification was first published in February 2013. The present version 1.2.1 is published in April 2016 and it is the first update of the specification.

Vendors have pointed out that it would be beneficial to include examples to make the specification easier to implement.

Implementations that was interoperable with other Reliable RTT implementations before the update of the specification will continue to be interoperable with the specification published in April 2016.

Presently the specification is implemented in Sweden, Denmark, Norway, Finland, Germany, Belgium, Thailand, Japan and Brazil.

If you represent a vendor and have the specification implemented in products or services in any other country please inform PTS about it, pts@pts.se.