Confirmation circuit for a two-way communication system

• US 4,092,597 A
• Filed: 08/10/1976
• Issued: 05/30/1978
• Est. Priority Date: 08/10/1976
• Status: Expired due to Term

• Current Assignee: ITT Corporation (ITT, Inc.)
• Original Assignee: International Telephone & Telegraph Corp. (ITT, Inc.)
• Inventors: Place, Harry
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Bookbinder, Marc E.
• Application Number:
  US05/713,303
• Time in Patent Office: 658 Days
• Field of Search: 325/165, 325/166, 325/183, 325/53, 325/55, 325/64, 325/37, 325/31, 343/225-227, 343/177, 340/311-313, 340/213.1, 340/213.2, 340/226, 340/408, 340/147 R, 178/3, 178/4.1 B, 331/108 C, 331/108 D, 331/154, 331/156, 179/84 VF, 179/84 T
• US Class Current: 455/703
• CPC Class Codes: H04W 88/027 using frequency address codes

Abstract

A two-tone decoder decodes simultaneously at least two calling tones each having different frequencies coupled from a calling station to a called station and produces a first control signal upon cessation of the two calling tones. A timer responding to the first control signals produces a second control signal in the form of a pulse having a predetermined duration. A relay is activated by the second control signal and couples a confirmation tone to the calling station from a confirmation tone generator in the called station for the predetermined duration of the second control signal.

Claims

1. A confirmation circuit to generate only a single confirmation tone for transmission from a base station to one of a plurality of remote two-way radios of a two-way communication system comprising:

first means disposed in said base station to decode at least two simultaneously received calling tones each having a different frequency transmitted from said one of said plurality of remote radios to said base station and to produce a first control signal upon cessation of said two calling tones;

second means disposed in said base station coupled to said first means responsive to said first control signal to produce a second control signal in the form of a pulse having a predetermined duration; and

third means disposed in said base station coupled to said second means responsive to said second control signal to transmit only said single confirmation tone having a single frequency different than the frequencies of said two calling tones from said base station to said one of said plurality of remote radios for said predetermined duration to indicate that said base station is ready to receive intelligence transmitted from said one of said plurality of remote radios.

2. A circuit according to claim 1, wherein said first means includes

a two tone decoder to detect the simultaneous presence of said two calling tones and produce said first control signal.

3. A circuit according to claim 2, wherein said second means includes

a timer coupled to said decoder responsive to said first control signal to produce said second control signal.

4. A circuit according to claim 3, wherein said third means includes

a tone generator to produce said confirmation tone, and

a relay coupled to said timer, said relay having at least one contact coupled to said tone generator to couple said confirmation tone to said calling station during the presence of said second control signal.

5. A circuit according to claim 1, wherein said second means includes

a timer coupled to said first means responsive to said first control signal to produce said second control signal.

6. A circuit according to claim 5, wherein said third means includes

a tone generator to produce said confirmation tone, and

a relay coupled to said timer, said relay having at least one contact coupled to said tone generator to couple said confirmation tone to said calling station during the presence of said second control signal.

7. A circuit according to claim 1, wherein said third means includes

a tone generator to produce said confirmation tone, and

a relay coupled to said second means, said relay having at least one contact coupled to said tone generator to couple said confirmation tone to said calling party during the presence of said second control signal.

8. A circuit according to claim 1, wherein said first means includes

two phase locked loops each responsive simultaneously to a different one of said two calling tones, and

a NOR gate coupled to each of said two phase locked loops to produce said first control signal.

9. A circuit according to claim 8, wherein said two phase locked loops and said NOR gate are integrated circuits.

10. A circuit according to claim 8, wherein said second means includes

a first integrated circuit timer coupled to said NOR gate, and

a first circuit coupled to said first timer to operate said first timer in a timing mode to produce said second control signal.

11. A circuit according to claim 10, wherein said third means includes

a second integrated circuit timer,

a second circuit coupled to said second timer to operate said second timer in a free-running mode to produce said confirmation tone, and

a relay coupled to said first timer, said relay having at least one contact coupled to said second timer to couple said confirmation tone to said calling station during the presence of said second control signal.

12. A circuit according to claim 1, wherein said second means includes

a first integrated circuit timer coupled to said first means, and

a first circuit coupled to said first timer to operate said first timer in a timing mode to produce said second control signal.

13. A circuit according to claim 12, wherein said third means includes

a second integrated circuit timer,

a second circuit coupled to said second timer to operate said second timer in a free running mode to produce said confirmation tone, and

a relay coupled to said first timer, said relay having at least one contact coupled to said second timer to couple said confirmation tone to said calling station during the presence of said second control signal.

14. A circuit according to claim 1, wherein said third means includes

an integrated circuit timer,

a circuit coupled to said timer to operate said timer in a free-running mode to produce said confirmation tone, and

a relay coupled to said second means, said relay having at least one contact coupled to said timer to couple said confirmation tone to said calling station during the presence of said second control signal.

15. A circuit according to claim 1, wherein said third means includes

a resistor-capacitor oscillator to produce said confirmation tone, and

a relay coupled to said second means, said relay having at least one contact coupled to said oscillator to couple said confirmation tone to said calling party during the presence of said second control signal.

16. A circuit according to claim 1, wherein said third means includes

an inductor-capacitor oscillator to produce said confirmation tone, and

a relay coupled to said second means, said relay having at least one contact coupled to said oscillator to couple said confirmation tone to said calling party during the presence of said second control signal.

17. A circuit according to claim 1, wherein said third means includes

a vibrating reed to produce said confirmation tone, and

a relay coupled to said second means, said relay having at least one contact coupled to said reed to couple said confirmation tone to said calling party during the presence of said second control signal.

18. A circuit according to claim 1, wherein said third means includes

a rotating mechanical device to produce said confirmation tone, and

a relay coupled to said second means, said relay having at least one contact coupled to said device to couple said confirmation tone to said calling party during the presence of said second control signal.