| 摘要 |
An alarm layout is designed to be connected to a subscriber line a, b or extension line, to which an ordinary telephone set T is connected or can be connected. The alarm layout contains a number of loudspeakers T1, T2 ... Tn which can be connected to the telephone line. The particular loudspeaker can be connected via assigned connection elements which arrange for the switching of the loudspeaker into and out from the particular line. The element for switching in the various loudspeakers has such a construction and reciprocal interaction that only one loudspeaker in the transmitter is connected to the telephone line a, b and the loudspeaker whose switch-on element was last actuated takes over the connection to the telephone line from a previously connected loudspeaker. The particular loudspeaker is arranged so that it can be cleared from a temporary current/voltage free condition of particular length on the line. When current/voltage is subsequently applied to the line once again, the particular loudspeaker is disconnected from the line and the ordinary telephone set is switched on for its normal use. <IMAGE> |
