| 摘要 |
<p>The invention refers to a telealarm system in which the exchange of messages between the peripheral units (CP) located with the users and the Switching Center (CC) is obtained through a connection line (DT) between each peripheral unit and the relating public telephone exchange (CTP) and through a data network (RD) between each telephone exchange and the Switching Center. The invention is inclusive of: first means (PM), located at the users' and suitable for inserting/extracting from the connection line one or more bidirectional data channels; second means (CS), located at each telephone exchange and suitable for inserting/extracting from the connection line the data channels and for handling the exchange of messages given with the first means, respectively with the Switching Center. A characteristic of the invention is the fact that the second means carry out a quick cyclic scan of the connection lines and of the user equipment in order to check their correct operation and the fact that said second means are enquired by the Switching Center with a scan slower than the previous one.</p> |
