| 摘要 |
A system for defining and maintaining an exclusion area (50) is presented, wherein the usage of cellular telephones is restricted, e.g. in a prison. The system comprises a base station and an associated computing system. The base station uses a network of directive antennas (40 to 47) in order to fit the coverage area to the particular exclusion area (50). The computing system performs the task of monitoring the cellular telephones inside the exclusion area (50) and also their entries and exits in and out of the exclusion area (50), respectively. Furthermore, the computing system intercepts all calls originating or terminating in the exclusion area (50) in order to control the usage of the cellular telephones located in said area. The computing system comprises: a first database storing the identities of the cellular telephones actually residing in the exclusion area (50); a second database storing the identities of the cellular telephones that have the permission of unconditionally making and receiving calls inside the exclusion area (50); a third database storing the details of calls completed in said exclusion area (50); and an audible response unit for sending audible messages to the cellular telephones of users inside the exclusion area (50). |
