DIGITAL BROADCASTING SYSTEM, MOBILE TERMINAL AND INFORMATIONSERVICE STATION

摘要

Ordinary data groups and index information indicating data names and memo ry locations of broadcasted data are transmitted in multiplex mode from a data broadcasting station, and received by an onboard terminal and/or an information service station through a data distribution part. The onboard terminal detec ts the information, which it does not hold, by referring to the index information, and presents a list of data names at the onboard display part. The service stati on separately stores the data groups and the index information provided from th e broadcasting station. In response to the download request from the onboard terminal, the service station examines whether the required data is located in SS memory part by referring to the index data, and captures the required data from external memory locations defined in the index information if the required data is not stored. The download data is encrypted with the cipher key provided by the requester and transmitted through a radio wave.