IDENTIFICATION BEACON

摘要

An identification beacon (B) is suitable to send out an identification signal (I) in response to a call-up signal (X), but preferably only if the call-up signal is from an approved source (C) and only when it is safe for the operator of the beacon for the identification signal to be transmitted. The beacon is thus provided with a receiver (R) and a transmitter (T). The receiver responds to a call-up signal of suitable parameters to cause the transmitter to send an interrogation signal (Y) to the caller. If the receiver then receives from the caller a satisfactory response (Z) to its interrogation signal, it causes the transmitter to transmit an identification signal (I). An optional override switch (O) is provided for the operator to prevent transmission of the identification signal in certain circumstances and a paging device (P) may be provided to alert the operator that the beacon is ready to transmit an identification signal in response to a call-up signal but is presently inhibited by him from doing so. The received signals may include control signals to change the nature of the signals to be transmitted or the criteria for acceptability of received signals; alternatively, these changes may be made automatically in response to a given number including one of signal interchanges with a controller.