Abstract: A radio receiver selects incoming traffic messages with respect to their validity for the approximate location of the radio receiver and includes a decoder. The radio receiver uses frequency data and coordinate data transmitted by the transmitters to determine its approximate location, and compares this approximate location to locations contained in the traffic messages. When there is conformity, a conformity signal serves to switch through the location-specific messages contained in the traffic messages to an audio output device.

Abstract: A radio warning receiver has a battery or accumulator (7) and means (8) for switching over to battery operation mode when network power (6) fails. Battery power is conserved by turning off (9) power to the end stage (3), placing the warning receiver in a so-called Stand-By Mode, until a control signal is detected (5) which indicates that a warning is to be broadcast. Then, power to the end stage is restored (11) for the duration of the warning broadcast.

Abstract: A warning broadcast system features control signal means, preferably digital, for confirming transmission path integrity prior to broadcast of a spoken warning message. A radio receiver (1) in an alarm center has an auxiliary carrier reception stage (4) which feeds a decoder (5). A coincidence circuit (6) has a first input (7) connected to the decoder output for inputting the received broadcast control signal and a second input (8) for inputting a directly-coupled control signal via a delay line (9) from the control signal generator (10) of the alarm center. When the control signals at the imputs (7, 8) of the coincidence circuit (6) coincide, an output signal (14) actuates a release (15) for the spoken warning message. If a plurality of transmitters (3) having different frequencies are networked, separate receivers (1,1', . . . ) set to the respective frequencies can feed their respective outputs (14, 14', . . . ) to an AND-gate (16) which triggers release (15).

Abstract: A programming unit (1) for ON-OFF switching of a siren or similar warning device can be provided with remote actuation capability by connecting it to a radio receiver tuner (27) and radio data signal decoder (25). The output of the signal decoder (25) is connected to a block decoder (12). Some of the block decoder outputs are connected to a comparison circuit (8) which attempts to match a broadcast siren address with a stored address uniquely identifying the associated siren program unit (1). In the event of a match, a set of flip-flops and gates controls loading of information at other block decoder outputs into a siren program buffer memory (4) and then into an end memory (3) attached to and controlling the program unit (1). After a siren program is performed, end memory (3) is reset.