ITU-T F.930 PDF

This Recommendation introduces telecommunications relay services (simply referred to as relay services). It also defines the reference model, requirements and functionality that facilitate, via an assistive intermediary (i.e., communication assistant, sign language interpreter or lipspeaker), communications between persons who have hearing or speech disabilities with hearing/speaking users over the voice telephony service in a functionally equivalent manner. The aim of this Recommendation is to enable multiple providers, even in different countries, to interwork with one another and allow all users to enjoy the same or similar experience

NOTE – Technical, regulatory and financial aspects vary from country to country. The Recommendation may include the statement such that there is no extra cost for persons both with and without disabilities to ensure functional equivalency. This edition of this Recommendation provides some of these aspects as initial consideration, e.g., framework and functionality that will impact the user experience globally. These aspects including global interoperability will be covered by further editions of this Recommendation.

It is recommended to follow the requirements and mechanisms described in this Recommendation when the relay services are supported.

It is also emphasized that the relay service is not solely about the media conversion but also includes call handling procedures (alerting, three-way call, and communication-assistant-leg release) and other emulation of user experiences in a functionally equivalent manner. Charging, protection against fraud and confidentiality of communication assistant are also relevant.