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US 3,946,315 AGranted
Single frequency signalling in a radiotelephone communication system with idle condition signal generator at one terminal activated by another terminal
AssigneeHughes Aircraft Company
InventorGalen F. Tustison
Life of this patent
Estimating the term…
Abstract
Single frequency signaling system which simulates the low level tone during the idle circuit condition even though the radio frequency carriers in the transmission link through a repeater have been turned off. Said system utilizes 2600 Hz detectors having long time constants to turn the transmitters on and off and to connect 2600 Hz oscillators to the receive lines to simulate the idle circuit condition.
Claims7
A communication system comprising at least two radio frequency terminals and a radio frequency repeater wherein at least one of the terminals comprises, in combination:
- a land based telephone system;
- a first radio frequency transmitter coupled to said land based telephone system;
- a first radio frequency receiver coupled to said land based telephone system;
- means for turning said first transmitter off whenever and so long as said telephone system generates an idle circuit condition signal to said first transmitter;
- means for generating an idle circuit condition signal;
- means for coupling said means for generating an idle circuit condition signal to said telephone system whenever an idle circuit condition signal is received by said first receiver for longer than a first time interval;
- and
- means for uncoupling said means for generating idle circuit condition signal from said telephone system upon the occurrence of a received radio frequency signal by said first receiver.
5 more elements
Dependencies are inferred from the claim text.