Telephone alarm system

• US 4,051,327 A
• Filed: 04/30/1976
• Issued: 09/27/1977
• Est. Priority Date: 04/30/1976
• Status: Expired due to Term

• Current Assignee: Pan-X Corporation
• Original Assignee: Pan-X Corporation
• Inventors: Rigsby, Jesse H.
• Primary Examiner(s): Robinson, Thomas A.
• Application Number:
  US05/681,834
• Time in Patent Office: 515 Days
• Field of Search: 179/5 R, 179/5 P, 179/2 A, 179/2 DP, 179/90 B, 179/84 VF
• US Class Current: 379/50
• CPC Class Codes: H04M 11/04 with alarm systems, e.g. fire, police or burglar alarm systems

Abstract

A telephone alarm system is provided including transmitter and receiver units for interconnection through telephone lines and exchange circuits. In response to an alarm signal, a line circuit in the transmitter unit is operated to an on-line condition and upon receipt of dial tone, a dialing circuit is operated to signal the exchange circuits to apply a ring signal to the receiver unit which responds to establish a completed connection. A request data tone signal is then transmitted from the receiver unit to the transmitter unit and in response, the transmitter unit transmits frequency shift keying signals generated from serial trains of pulses developed by a converter circuit which is controlled from parallel connections to a plurality of output lines of a memory circuit. The memory circuit stores coded word information which uniquely identifies the transmitter unit and also stores information as to the telephone number of the receiver unit. The dialing circuit is also controlled from the memory circuit and includes a counter which counts clock pulses according to bit information supplied in parallel word groups from the memory. The receiver unit responds to the frequency shift keying signals to develop serial trains of pulses which are applied to a converter circuit operative to develop signals applied in parallel to a teleprinter or the like to display the code work unique to the transmitter unit. Circuits are provided in the units for performing various functions including redialing if no dial tone is detected, re-transmission of the data request tone signal if a parity check in the receiver unit is not satisfactory, re-transmission of data and for causing each unit to go off-line after a predetermined time interval.

Claims

1. In a telephone alarm system, transmitter and receiver units for connection to first and second pairs of telephone lines interconnectable through a telephone exchange system, said transmitter unit including a line circuit for establishing a low impedance connection between the first pair of telephone lines and for receiving a dial tone signal back from the exchange system, a memory in said transmitter unit for storing information identifying said receiver unit and for storing a code word unique to said transmitter unit, a clock circuit for supplying signals to said memory, dialing means in said transmitter unit controllable from said memory for transmitting dial signals through the first pair of telephone lines to the exchange system, means responsive to receipt of a dial tone signal for applying clock signals from said clock circuit to said memory and transmission of said dial signals to the exchange system, a line circuit in said receiver unit for responding to a ring signal applied through the second pair of lines from the exchange system and for establishing a connection to the second pair of lines and to thereby complete a connection between said transmitter and receiver units through the telephone lines and the exchange system for signal transmission therebetween, means in said receiver unit for transmitting a request data tone signal following the establishment of said completed connection, request data tone detector means in said transmitter unit for detecting a request data tone signal transmitted back from said receiver unit through said completed connection, code signal transmission means in said transmitter unit controllable from said memory for transmitting keyed signals to said receiver unit through said completed connection, means responsive to detection of a request data tone signal by said detector means for applying clock signals from said clock circuit to said memory and transmission of said keyed signals to said receiver unit through said completed connection, signal receiving means in said receiver unit arranged for responding to said transmitted keyed signals to develop output signals, and means for applying said output signals to display means to display said code word unique to said transmitter unit.

2. In a telephone alarm system, transmitter and receiver units for connection to first and second pairs of telephone lines interconnectable through a telephone exchange system, said transmitter unit including a line circuit for establishing a low impedance connection between the first pair of telephone line and for receiving a dial tone signal back from the exchange system, dialing means in said transmitter unit responsive to receipt of a dial tone signal for transmitting dial signals through the first pair of telephone lines to the exchange system, a line circuit in said receiver unit for responding to a ring signal applied through the second pair of lines from the exchange system and for establishing a connection to the second pair of lines and to thereby complete a connection between said transmitter and receiver units through the telephone lines and the exchange system for signal transmission therebetween, means in said receiver unit for transmitting a request data tone signal following the establishment of said completed connection, request data tone detector means in said transmitter unit for detecting a request data tone signal transmitted back from said receiver unit through said completed connection, a memory in said transmitter unit for storing a code word unique to said transmitter unit, code signal transmission means in said transmitter unit controlled from said request data tone detector means and from said memory for transmitting keyed signals to said receiver unit through said completed connection, signal receiving means in said receiver unit arranged for responding to said transmitted keyed signals to develop output signals, and means for applying said output signals to display means to display said code word unique to said transmitter unit, said memory being operative to store coded word information in the form of a plurality of word groups each including a plurality of bits and said memory having output terminals on which a plurality of signal voltages are simultaneously developed corresponding to said plurality of bits of each word group, a clock circuit in said transmitter unit, said code signal transmission means in said transmitter unit including a converter circuit having input terminals coupled to said clock circuit and to said output terminals of said memory and arranged to develop serial trains of pulses with the number of pulses in each train corresponding to signal voltages simultaneously developed in said group of output terminals of said memory, and a keying circuit in said transmitter unit responsive to each of said serial trains of pulses and arranged to apply a corresponding serial train of keyed signals through said completed connection to the receiver unit.

3. In a system as defined in claim 2, said signal receiving means in said receiver unit including means responsive to transmitted keyed signals to produce serial trains of pulses corresponding to those produced by said converter circuit in said transmitter unit, and converter means in said receiver unit having a plurality of output terminals and responsive to each train of pulses to produce voltage signals on said output lines corresponding to the bits of the word group in the transmitted information.

4. In a telephone alarm system, transmitter and receiver units for connection to first and second pairs of telephone lines interconnectable through a telephone exchange system, said transmitter unit including a line circuit for establishing a low impedance connection between the first pair of telephone lines and for receiving a dial tone signal back from the exchange system, dialng means in said transmitter unit repsonsive to receipt of a dial tone signal for transmitting dial signals through the first pair of telephone lines to the exchange system, a line circuit in said receiver unit for responding to a ring signal applied through the second pair of lines from the exchange system and for establishing a connection to the second pair of lines and to thereby complete a connection between said transmitter and receiver units through the telephone lines and the exchange system for signal transmission therebetween, means in said receiver unit for transmitting a request data tone signal following the establishment of said completed connection, request data tone detector means in said transmitter unit for detecting a request data tone signal transmitted back from said receiver unit through said completed connection, a memory in said transmitter unit for storing a code word unique to said transmitter unit, code signal transmission means in said transmitter unit controlled from said request data tone detector means and from said memory for transmitting keyed signals to said receiver unit through said completed connection, signal receiving means in said receiver unit arranged for responding to said transmitted keyed signals to develop output signals, and means for applying said output signals to display means to display said code word unique to said transmitter unit, a parity latch circuit in said receiver unit operated from an unlatched condition to a latched condition in response to operation of said request data tone transmitter means, means in said signal receiving means for operating said parity latch circuit to said unlatched condition in response to performance of a satisfactory pariy check with respect to said received keyed signals, and means operative following the end of receipt of keyed signals for re-instituting operation of said request data tone transmission means when said parity latch circuit then remains in said latched condition.

5. In a system as defined in claim 4, said request data tone dectector means and said code signal transmission means in said transmitter unit being arranged to respond to retransmission of a request data tone through said completed connection for re-transmitting said keyed signals through said completed connection.

6. In a system as defined in claim 5, an enable latch circuit in said transmitter unit arranged to be activated from an unlatched condition to a latched condition in response to an alarm signal, an on-line loop circuit coupled to said enable latch circuit and including timer means operable for a predetermined time interval after activation, means activating said timer means in response to placing of said enable latch circuit in a latched condition, means responsive to activation of said enable latch circuit to said latched condition and to activation of said timer means for operating said line circuit to establish said low impedance connection, means coupling said request data tone detector to said enable latch circuit to activate said enable latch circuit to said unlatched condition in response to detection of a request data tone signal, and means operative at the end of said predetermined time interval and following activation of said enable latch circuit to said unlatched condition to operate said line circuit to an off-line condition.

7. In a transmitter unit for a telephone alarm system, a line circuit for connection to a pair of telephone lines, a memory circuit for storing code word information uniquely associated with said transmitter unit, said code word information being in the form of a plurality of word groups each including a plurality of bits and said memory circuit having output terminals on which a plurality of signal voltages are simultaneously developed corresponding to said plurality of bits of each word group, a clock circuit, a converter circuit having input terminals coupled to said clock circuit and to said output terminals of said memory circuit and arranged to develop serial trains of pulses with the number of pulses in each train corresponding to signal voltages simultaneously developed on said group of output terminals of said memory circuit, a keying circuit responsive to each of said serial trains of pulses and arranged to apply a corresponding serial train of keyed signals through said line circuit to the telephone lines, and control means for responding to an alarm condition and controlling operation of said memory and converter circuits and the application of said serial trains of keyed signals through said line circuit to the telephone lines.

8. In a transmitter unit as defined in claim 7, address means coupled to said clock circuit and to said memory circuit for successively developing signal voltages on said memory output terminals corresponding to successive word groups of stored information, and strobe means coupled to said clock circuit for controlling operation of said converter circuit in timed relation to the operation of said address means.

9. In a transmitter unit as defined in claim 7, said control means comprising a request data tone detector arranged to detect a tone of a predetermined frequency transmitted from the telephone lines through said line circuit and to develop a corresponding output signal, and request data control means responsive to said request data tone detector output signal for initiating operation of said memory, converter and keying circuits to cause transmission of serial trains of keyed signals through said line circuit to the telephone lines.

10. In a transmitter unit as defined in claim 9, said request data control means including a latch circuit operable from an unlatched condition to a latched condition in response to said request data tone detector output signal, and end of transmission detector means responsive to a predetemined code signal of said memory circuit output terminals for operating said latch circuit from said latched condition to said unlatched condition.

11. In a transmitter unit as defined in claim 7, said memory circuit being arranged for storing additional word groups of bits of information with the word groups corresponding to digits of a telephone number assigned to a receiver unit and said memory circuit having a second group of output lines on which an additional plurality of signal voltages are simultaneously developed corresponding to bits of each of said additional word groups of information, and dialing means controlled from said additional plurality of output lines for applying dialing signals through said line circuit to the telephone lines, said control means being operative for controlling said dialing means for initially applying said dialing signals to the telephone lines and for thereafter applying said serial trains of keyed signals through said line circuit to the telephone lines.

12. In a transmitter unit as defined in claim 11, said dialing means comprising counter means responsive to clock signals from said clock circuit and coupled to said additional plurality of output lines of said memory circuit for counting until the number of pulses applied correspond to a word group of information presented by signals on said additional plurality of output lines, means for applying clock pulses counted by said counter means through said line circuit to the telephone lines, and address means for controlling said memory after said counter means counts a number of pulses corresponding to one word group to develop signal voltages on said additional output terminals corresponding to a successive word group.

13. In a transmitter unit as defined in claim 11, said converter circuit having input terminals coupled both to said group of output terminals corresponding to said word groups of coded information and said additional output terminals corresponding to digits of a telephone number assigned to a receiver unit for developing serial trains of pulses with the number of pulses in each train corresponding to both groups of information.

14. In a transmitter unit as defined in claim 7, said keying circuit being arranged to develop keyed signals in the form of signals shifted between two tones of different frequencies.

15. In a transmitter unit for a telephone alarm system, a line circuit for connection to a pair of telephone lines, a memory circuit for storing bits of information in word groups, each word group corresponding to a digit of a telephone number of a receiving unit, said memory circuit having a group of output lines on which a plurality of signal voltages are simultaneously developed corresponding to bits of a presented word group, a clock circuit for supplying clock signals, dialing means comprising counter means responsive to clock signals from said clock circuit and coupled to said group of output lines to count until the number of applied clock pulses corresponds to the word group of information presented by signals on said group of output lines, means for applying clock pulses counted by said counter means through said line circuit to the telephone lines, address means for operating said memory circuit after said counter means counts a number of pulses corresponding to one word group to develop signal voltages on said output lines corresponding to a successive word group, and control means for responding to an alarm condition to control said memory circuit and said dialing means.

16. In a transmitter unit as defined in claim 15, said memory circuit being arranged to store bits of information forming a final end of data code word, and means responsive to development of signal voltages on said memory circuit output lines corresponding to said end of data code word for placing said memory circuit in an initial condition in which the first word group thereafter presented is that corresponding to the first digit of the telephone number of a receiver unit.

17. In a transmitter unit for a telephone alarm system, a line circuit for connection to a pair of telephone lines connected to a telephone exchange system, said line circuit being operative from an off-line condition to an on-line condition for establishing a low impedance connection between the telephone lines and for receipt and transmission of signals from and to the telephone lines, a dial tone detector circuit coupled through said line circuit to the telephone lines, dialing means controlled from said dial tone detector circuit for transmission of dial signals through said line circuit and the telephone lines for establishing a connection to a receiver unit through the exchange system, a request data tone detector circuit for receiving a request data tone signal transmitted back from a receiver unit, data transmission means controlled from said request data tone detector circuit for transmission of data through said line circuit, the telephone lines and the exchange system to a receiving unit, an enable latch circuit arranged to be activated from an unlatched condition to a latched condition in response to an alarm singal, an on-line loop circuit coupled to said enable latch circuit and including timer means operable for a predetermined time interval after activation, means for activating said timer means in response to placing of said enable latch circuit in a latched condition, means responsive to activation of said enable latch circuit to said latched condition and activation of said timer means for operating said line circuit to said on-line condition, means coupling said request data tone detector to said enable latch circuit to activate said enable latch circuit to said unlatched condition in response to detection of a request data tone signal, and means operative at the end of said predetermined time interval and following activation of said enable latch circuit to said unlatched condition to operate said line circuit to said off-line condition.

18. In a transmitter unit as defined in claim 17, means operative at the end of said predetermined time interval and when said enable latch circuit remains in said latched condition for temporarily placing said line circuit in said off-line condition and then re-activating said timer means for activation of said line circuit to said on-line condition.

19. In a transmitter unit as defined in claim 17, means for resetting and re-activating said timer means in response to receipt of a request data tone signal to operate for said predetermined time interval thereafter.

20. In a transmitter unit as defined in claim 17, said on-line loop circuit comprising a counter, and an on-line clock circuit for supplying clock signals to said counter.

21. In a receiver unit for a telephone alarm system, a line circuit for connection to a pair of telephone lines and including means responsive to an applied ring signal and means for thereafter establishing a connection to the telephone lines for transmission and receipt of signals to and from a transmitter unit, means for transmitting a request data tone signal through said connection, means for receiving keyed signals transmitted back from a transmitter unit through said connection, means responsive to received keyed signals to produce serial trains of pulses each train corresponding to at least one word group of bit information with each word group corresponding to a character of a transmitted code word uniquely identifying a transmitter unit, converter means having a plurality of output terminals and responsive to each train of pulses to simultaneously produce voltage signals on said output lines corresponding to the bits of the word group in the transmitted information and means for applying said voltage signals to display means to display the characters of the transmitted code word.

22. In a receiver unit as defined in claim 21, a parity latch circuit operated from an unlatched condition to a latched condition in response to operation of said request data tone transmitting means, means for operating said parity latch circuit to said unlatched condition in response to performance of a satisfactory parity check with respect to received keyed signals, and means operative following the end of receipt of keyed signals for re-instituting operation of said request data tone transmission means when said parity latch circuit then remains in said latched condition.