A system is described for assisting the hard of hearing in the use of the telephone, in which an in-line text display is inserted in the telephone line before a standard telephone. The in-line display blocks text related digital communications signals to the standard telephone and decodes the text related...http://www.google.de/patents/US6075841?utm_source=gb-gplus-sharePatent US6075841 - In-line text display for telephone terminal employing data filtering
