IDENTIFICATION SIGNAL NONAPPROVED USE DETECTING METHOD

摘要

12 To differentiate between different subscriber stations of a message transmission system, so-called identifications can be used. By listening-in on the exchange of information between the subscriber station and an exchange over a message transmission channel a fraudulent user can overhear the identification and consequently utilize the services of the exchange by imitation of the external identification. To enable the detection in the exchange of an illegally copied identification of a subscriber station, the exchange transmits a continuously changing encoding rule for forming the identification of the subscriber station, or the identification of the subscriber station is based on combining fixed and variable data.