| 摘要 |
A terminal serving a group of subscriber lines, some of which are invariably paired with remote stations through so-called "hot-line" connections, has a line concentrator/distributor from which a lesser number of line links extend to an automatic exchange at a nodal point of a data and/or voice telecommunication system. The line concentrator/distributor is controlled by a marker connected via a separate signaling channel with a line-control unit at the nodal point, that unit including a classifier which stores information fully identifying each associated subscriber line in terms of call number and class of service while also correlating the address of each line link on the terminal side with that on the address side. A programmer in the line-control unit successively scans the several line links in respective sampling phases of a recurrent TDM cycle and also establishes a service phase in that cycle during which an engagement message from the marker, arriving over the signaling channel at an input/output circuit of that unit, is relayed to the classifier which transmits the identity of the calling subscriber line and of its assigned line link as well as the service class of the subscriber to the programmer for the initiation of a call-extending program in the corresponding sampling phase. The line-control unit further includes checking circuits for signaling an alarm condition in the event of a malfunction or an erroneous selection.
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