REMOTE CONDITION MONITORING DEVICE

• US 3,787,624 A
• Filed: 05/22/1972
• Issued: 01/22/1974
• Est. Priority Date: 05/22/1972
• Status: Expired due to Term

• Current Assignee: Arnold Spitalny, George Brettbart, Stanley R. Sporn
• Original Assignee: Arnold Spitalny, George Brettbart, Stanley R. Sporn
• Inventors: Spitalny, Arnold, Brettbart, George, Sporn, Stanley R.
• Primary Examiner(s): Claffy, Kathleen H.
• Assistant Examiner(s): Stewart, David L.
• Application Number:
  US05/255,662
• Time in Patent Office: 610 Days
• Field of Search: 179/5R,2A 340/408
• US Class Current: 379/39
• CPC Class Codes: H04M 11/04 with alarm systems, e.g. fire, police or burglar alarm systems

Abstract

A remote condition monitoring device is operative to connect into preexisting telephone station lines when a monitored physical condition exceeds preset limits. An incoming call causes completion of the calling circuit by simulating the lifting of a receiver at the called station. A warning tone is produced which is audible to the caller over the completed telephone calling circuit.

Claims

1. A remote-condition monitoring apparatus for use in conjunction with a preexisting telephone system comprising lead means including first and second leads adaptable for connection to preexisting telephone station lines, monitoring means operative to determine when a preselected measurable physical parameter exceeds a present limit, ring detector means for detecting the electrical ringing signal on said lead means representing the presence of an incoming telephone call on said preexisting telephone station lines to produce a ring detector signal in response to said ringing signal, first switching means operative in response to said monitoring means to selectively interconnect said lead means and said incoming call detecting means when said preset limit is exceeded, electrical simulating means operative to provide an electrical simulation signal equivalent to that produced at the central switching office of said preexisting telephone system by the lifting of a telephone receiver to thereby cause the completion of the calling circuit for said incoming telephone call by said central switching office, second switching means connected to the output of said ring detector means and operative in response to said ring detector signal to connect said electrical simulating means to the output of said lead means whereby said ringing signal is applied to said electrical simulating means to initiate said electrical simulation signal, and tone generator means connected to said electrical simulating means and operative in response thereto to produce an audible tone over said completed callIng circuit.

2. A remote-condition monitoring apparatus according to claim 1 wherein said ring detector means comprises timing means connected to said second switching means for causing said second switching means to disconnect said electrical simulating means from said lead means output upon expiration of a preselected period of time from said connection thereto, thereby controlling the duration of said electrical simulation signal.

3. A remote-condition monitoring apparatus according to claim 2 wherein said first switching means is connected in series with said first lead of said lead means.

4. A remote-condition monitoring apparatus according to claim 3 wherein said lead means comprises a full-wave rectifier bridge having first and second input terminals, said bridge first input terminal being connected to said first switching means and said bridge second input terminal being connected in series with said second lead of said lead means.

5. A remote-condition monitoring apparatus according to claim 4 wherein said ring detector means includes a unilaterally-conductive device, a charging resistor and a charging capacitor in series arrangement connected across the output of said lead means.

6. A remote-condition monitoring apparatus according to claim 5 wherein said full-wave rectifier bridge comprises first and second output terminals connected respectively to the ends of the series arrangement of said unilaterally conductive device, said charging resistor and said charging capacitor.

7. A remote-condition monitoring apparatus according to claim 6 wherein said ring detector means further includes a zener diode connected at one end to the junction of said unilaterally-conductive device and said charging resistor and at its other end to said second switching means.

8. A remote-condition monitoring apparatus according to claim 7 wherein said electrical simulating means comprises a load resistor having one end thereof connected to the junction of said unilaterally-conductive device and said bridge rectifier first output terminal and the other end thereof to said second switching means.

9. A remote-condition monitoring apparatus according to claim 8 wherein said second switching means comprises first and second current limiting resistors serially connected to the other end of said zener diode, and a double-pole relay having a relay coil connected between said second current limiting resistor and said bridge rectifier second output terminal.

10. A remote-condition monitoring apparatus according to claim 9 wherein said timing means comprises said charging capacitor, said second current limiting resistor and said relay coil.

11. A remote-condition monitoring apparatus according to claim 10 wherein said double-pole relay comprises a first pair of switching contacts connected between the junction of said charging resistor and said charging capacitor and the junction of said first and second current limiting resistors respectively.

12. A remote-condition monitoring apparatus according to claim 11 wherein said double-pole relay includes a second pair of switching contacts connected between the other end of said load resistor and said bridge rectifier second output terminal.

13. A remote-condition monitoring apparatus according to claim 12 wherein said first and second pairs of said relay switching contacts are poled in the same direction.

14. A remote-condition monitoring apparatus according to claim 13 wherein said tone generator means comprises an oscillator having a pair of input terminals and a pair of output terminals, said oscillator input terminals being connected across said load resistor, and an audio speaker connected across said tone generator output terminals.