| 摘要 |
The invention relates to a method and a circuit arrangement to carry out the method for monitoring a data transmission system comprising fixed and mobile transceiver stations where the latter are in radio contact with the former, and a central station, connected to the fixed stations, whose continuously transmitted call telegrams are received by the fixed stations and forwarded to the mobile stations which immediately transmit their reply telegrams to the central station, in each case via the fixed stations currently assigned to them. According to the invention, the call telegram contains a synchronisation word which is evaluated in the fixed station, which, once the call telegram has been received and forwarded, waits to see whether a reply telegram arrives at a mobile station. If it does not arrive, a short telegram with monitoring messages is transmitted to the central station (Z) where it is evaluated (Fig. 1). This method ensures that the operational capacity of the entire transmission path, including all modems, lines and radio units, is constantly monitored automatically. <IMAGE> |
