DATENUEBERTRAGUNGSEINRICHTUNG ZUM FUEHLEN DES AUFENTHALTSORTES UND/ODER DER ZUSTANDSMERKMALE VON IN EINEM GEGEBENEN BEREICH ODER GEBIET BEFINDLICHEN PERSONEN UND/ODER OBJEKTEN

A data transmission and monitoring/controlling system comprising transmitters 5 and receivers, in which district or local receivers contactable by local networks receive, evaluate and/or transmit signals of code transmitters placed in an area defined by an antenna or loop, the code senders operating with random periodicity and transmitting in FM code of constant length having at most three conditions or states. A gate 2 is connected between an oscillator 1 and a frequency synthesiser 3 which controls a switch 4 which frequency modulates a transmitter 5. Modulation information signals are provided via code transmitters 6 and 7. Gate 2 is controlled by a random generator 10, an enable circuit 8 and an inhibit circuit 9. The gate 2 and switch 4 are described (Figure 2). The transmitter 5 and the receiver are described (Figures 3 and 4) respectively.