| 摘要 |
Captioned telephones are devices intended to provide text captions to persons needing assistance with telephone communications by using the services of a relay interposed between the assisted user and the hearing user, the relay providing the captioning for the assisted user. The service can be delivered over a single telephone line, or if the assisted user has two telephone lines available for the captioning service, additional features and advantages are possible in the delivery of the service to the user. During a telephone conversation, the captioned telephone device uses echo cancellation to cancel the voice of the assisted user from the second telephone line so that the relay does not hear the voice of the assisted user, so the relay can caption all the words on the second telephone line without causing confusion to the assisted user. |
