00000nam 2200000zi 4500 9.891732 CaOODSP 20221107172952 m o d f cr mn||||||||| 200923s1978 onca ob f000 0 eng d CaOODSP eng rda CaOODSP n-cn--- Co24-3/8-697-1978E-PDF Bown, H. G., author. A general description of Telidon : a Canadian proposal for videotex systems / by H.G. Bown, C.D. O'Brien, W. Sawchuk and J.R. Storey. Ottawa : Communications Research Centre, 1978. 1 online resource (iii, 26 pages) : illustrations. text txt rdacontent computer c rdamedia online resource cr rdacarrier CRC technical note ; no. 697-E Issued also in French under title: Description générale du Télidon : proposition canadienne concernant les systèmes vidéotex. "Technology and Systems Branch." "December 1978." Digitized edition from print [produced by Innovation, Science and Economic Development Canada]. Some pages rotated in this copy. Includes bibliographical references (pages 15-16). "Videotex systems allow easy access, by the general public, to large computer-based information sources which contain pages of information to be displayed on suitably supplemented television receivers or newly designed Videotex terminals. Each page of information may contain both textual and graphic images. Organizations in a number of European countries are promoting standards for Videotex systems based on an alpha-mosaic approach which limits the resolution of graphic images to a format far below the resolution capabilities of the display medium. With this approach, the future development of Videotex systems will be constrained, because images at the information source are described in a terminal-dependent manner with the same alpha-mosaic format used for their displays. Once this format is adopted it will be difficult, if not impossible, to update information source files in a manner suitable for both present and future, more advanced, Videotex terminals. A new terminal-independent method of describing images is suggested in this report on the Canadian Telidon Videotex system. Images are described as either alpha-geometric or alpha-photographic images by means of Picture Description Instructions (PDI's). This new approach permits the growth of large information bases, through terminal independence, which would not have to change to accommodate new developments and improvements as new technologies become available in the foreseeable future"--Abstract, page 1. Issued also in print format. Telidon (Data transmission system) Videotex systems Canada. Communications Research Centre (Canada), issuing body. Description générale du Télidon : (CaOODSP)9.891734 CRC technical note ; no. 697-E. (CaOODSP)9.882494 PDF 1.96 MB https://publications.gc.ca/collections/collection_2020/isde-ised/Co24/Co24-3-8-697-1978-eng.pdf