The Institute expanded into medical and technological research during the 1960s and 1970s, being a key player in the development of NHS provided behind-the-ear hearing aids. During the 1980s it developed the Telephone Exchange for the Deaf, a pioneering relay service allowing telephone users and deaf "textphone" users to communicate with each other using a third-party operator to relay voice and text communication. This became the service known as Typetalk in 1991, funded by BT but operated on their behalf by RNID until 7 December 2009 when the RNID stepped down from the service. It is now solely owned, run and managed by BT alone. In March 2009 the name of the Typetalk service was changed to Text Relay.