Method and apparatus for automatically establishing telephone communication links

• US 4,518,822 A
• Filed: 03/08/1983
• Issued: 05/21/1985
• Est. Priority Date: 04/03/1981
• Status: Expired due to Fees

• Current Assignee: Cooper Industries, Inc. (Eaton Corporation PLC.)
• Original Assignee: Mcgraw-Edison Company (Eaton Corporation PLC.)
• Inventors: Martinez, Louis
• Primary Examiner(s): Rubinson, Gene Z.
• Assistant Examiner(s): Brady, W. J.
• Application Number:
  US06/472,869
• Time in Patent Office: 805 Days
• Field of Search: 179/2 E, 179/2 EA, 179/2 EB, 179/2 EC, 179/2 AS, 179/2 R, 179/2 A, 179/2 AM, 179/2 B, 179/2 DP, 179/5 P, 179/5 R, 340/311.1, 340/825.44-825.48, 340/539, 455/102, 455/105
• US Class Current: 379/102.02
• CPC Class Codes: G08B 27/008 with transmission via TV or radio broadcast

Abstract

Public alert and advisory systems for the communication of emergency and/or other information from one or more central locations to a plurality of remote locations, such as, by way of example, information regarding a nuclear accident and evacuation procedures. This system utilizes conventional programming stations such as AM, FM or TV stations, central transmitting equipment, with the emergency information being modulated by a second modulation technique differing from the first modulation technique for the ordinary programming so that conventional manually operated programming receivers will not be responsive to the emergency information. The receivers of the system however, are responsive to the transmitted emergency information, so as to sound a warning alarm, display codes relating to evacuation or other information and/or receive and present audio information depending upon the specific configuration of the system. Normally the remote receivers are given recognition codes so that the receiver may be given different emergency information, either on an individual or on a group to group basis. Fault detection is provided by configuring the remote receivers to automatically provide a fault indication if not periodically reset by the communications link. A unique telephone link, also disclosed, can be used for reliability testing or for ordinary data communication. Various embodiments and features are disclosed.

Claims

1. Apparatus for establishing a telephone communications link between a calling location and a remote location comprising

a central transmitter station including first transmitter modulation means for modulating a signal to be transmitted with programming, using a first modulation technique, for transmission of the programming to manually controllable first receivers having first receiver demodulation means responsive to signals modulated with said first modulation technique for the reception and demodulation of said modulated signal to allow selective perception of the programming by members of the public,

second modulation means coupled to said central transmitter station for modulation of the signal to be transmitted with a request to answer signal utilizing a second modulation technique to which said first receiver demodulation means are not primarily responsive,

at least one second receiver, each of said second receivers having second receiver demodulation means responsive to signals modulated with said second modulation technique for the reception and demodulation of the transmitted signal to provide the request to answer signal at the respective remote location,

phone control means coupled to each of said second receivers for receiving said request to answer signal and for providing a phone control signal in response thereto, and

phone answering means coupled to each of said phone control means and a phone line and being responsive to said phone control signal and a ring signal on the phone line to automatically terminate the ring signal and hold the phone line upon receipt of a call.

2. The apparatus of claim 1 wherein said phone control means is a means for providing the phone control signal to said phone answering means for a predetermined length of time after receipt of said request to answer signal.

3. The apparatus of claim 1 further comprised of a modem coupled to each of said phone answering means for data communication over the phone line.

4. The apparatus of claim 3 further comprised of means coupled to each of said second receivers and modems for synchronizing a data clock for said data communication with a signal broadcast by said central transmission station.

5. The apparatus of claim 4 having a plurality of second receivers, wherein said second modulation means is a means for modulation of the signal to be transmitted with identification codes utilizing the said second modulation technique, and wherein each said phone control means is a means for receiving said identification codes and for providing a phone control signal upon receipt of a predetermined identification code associated therewith.

6. Apparatus for establishing a telephone communication link between a calling location and remote locations comprising

a central transmitter for modulating a signal to be transmitted with programming using a first modulation technique for transmission and selective reception of the programming by members of the public by using first receivers in accordance with standard broadcast techniques,

second modulation means coupled to said central transmitter station for modulation of the signal to be transmitted with at least one command signal utilizing a second modulation technique to which said first receivers are not primarily responsive,

a plurality of second receivers at remote locations, each of said second receivers having second receiver demodulation means responsive to signals modulated with said second modulation technique for the reception and demodulation of the transmitted signal to provide said at least one command signal at the respective remote location,

answer means coupled to each of said second receivers and a phone line, said answer means being responsive to said at least one command signal to detect the presence of a ring signal on said phone line, at a called location, to automatically provide an off hook signal to hold the phone line in response thereto and to couple a remote location data communication device to the phone line, and

means coupled to a phone line at the calling location for communicating said at least one command signal to said second modulation means, for dialing the phone number associated with the phone line at at least one remote location and for coupling a data communication device at the calling location to the phone line.

7. The apparatus of claim 6 wherein said command signal comprises, at least in part, an identification code, and wherein each of said answer means is responsive to the identification code associated therewith.

8. The apparatus of claim 7 wherein said data communication device at the calling location and said data communication devices at the called locations are synchronized in data transfer rates by the signal transmitted by said central transmitter.

9. The apparatus of claim 8 wherein said data communication device at the calling location and said data communication devices at the called locations are repetitively resynchronized by special synchronizing signals broadcast by said central transmitter station.

10. Apparatus for establishing a telephone communication link between a calling location and remote locations comprising

a central AM broadcast station having first modulation means for modulation of a signal to be transmitted with programming using double sideband amplitude modulation for transmission of the programming for the selective reception by members of the public using conventional AM receivers,

second modulation means coupled to said AM broadcast station for modulation of the signal to be transmitted with at least one command signal utilizing narrow band quadrature modulation of the carrier of the amplitude modulated signal,

a plurality of second receivers at remote locations, each of said second receivers having demodulation means responsive to the narrow band quadrature modulation of an AM carrier of the transmitted signal to provide said at least one command signal at the respective remote location,

answer means coupled to each of said second receivers and a phone line, said answer means being responsive to said at least one command signal to detect the presence of a ring signal on said phone line, to automatically provide an off hook signal to hold the phone line in response thereto and to couple a remote location data communication device to the phone line, and

means coupled to a phone line at the calling location for communication of said at least one command signal to said second modulation means, for dialing the phone number associated with the phone line at at least one remote location and for coupling a calling location data communication device to the phone line.

11. The apparatus of claim 10 wherein said command signal comprises, at least in part, an identification code, and wherein each of said answer means are responsive to the identification code associated therewith.

12. The apparatus of claim 11 wherein said calling location data communication device and said data communication devices at the called location are synchronized in data transfer rates by the carrier of the AM signal transmitted by said central transmitter.

13. The apparatus of claim 12 wherein the signal to be transmitted is modulated with a digital command signal by shifting the phase of the carrier of the amplitude modulated signal first in one direction and then in the opposite direction for transmission of a first logic level, and by not shifting the phase of the carrier of the amplitude modulated signal for transmission of a second logic level, whereby any digital command signal may be transmitted without causing any net carrier phase or frequency shift.

14. The apparatus of claim 12 wherein said calling location data communication device and said called location data communication devices are repetitively resynchronized by special synchronizing signals broadcast by said broadcast station.