Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M1/00—Substation equipment, e.g. for use by subscribers
  • H04M1/66—Substation equipment, e.g. for use by subscribers with means for preventing unauthorised or fraudulent calling
  • H04M1/663—Preventing unauthorised calls to a telephone set
  • H04M1/665—Preventing unauthorised calls to a telephone set by checking the validity of a code
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M1/00—Substation equipment, e.g. for use by subscribers
  • H04M1/26—Devices for calling a subscriber
  • H04M1/53—Generation of additional signals, e.g. additional pulses
  • H04M1/54—Arrangements wherein a dial or the like generates identifying signals, e.g. in party-line systems
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M1/00—Substation equipment, e.g. for use by subscribers
  • H04M1/57—Arrangements for indicating or recording the number of the calling subscriber at the called subscriber's set
  • H04M1/573—Line monitoring circuits for detecting caller identification

Definitions

• This invention relates to telephone or intercom systems or the like.
• each individual station or line terminal is located by the caller entering a specific number combination. Any additional selectivity at this stage however such as the identity of a particular call recipient is not possible.
• this invention discloses an improved telephone system whereby additional information can be conveyed during the initial placing of a call by means of the entry of a secondary code number which preferably follows the line number.
• each ca l ler could be assigned a secondary code number.
• the initiation of a pre-selected ringing tone would be used to convey the identity of the caller.
• any telephone anywhere in the world could be used even without computerised facilities to contact a specific person. Such person moreover would become aware of the callers identity before the telephone had to be answered.
• the secondary code number could be changed as required.
• the currently preferred embodiment of this invention comprises an electronic unit that is connectable between a telephone subscribers line terminal and the telephone appliance.
• the unit preferably consists of three relays and five electronic subsystems. These are illustrated in the accompanying figures as follows:
• Figure 1 shows a system block diagram of the unit
• Figure 2 is a schematic diagram of the ring detector and remote on-hook detector
• Figure 3 is a schematic diagram of the dial- pulse counter.
• Figure 4 is a schematic diagram of the acoustic signal generator (block 1) ,
• Figure 5 is a schematic diagram of the acoustic signal generator (block 2) .
• relay 1 In its unenergised state relay 1 connects the incoming line to the ring detector sub-system 2. When energised by an output from the ring detector the incoming line is switched to relay 3.
• relay 3 In its unenergised state relay 3 is connected onto a 600 ohm telephone at the input of the pulse counter 4. This simulates the handset going off-hook and thus signals the exchange to make the audio connection between subscribers. When it is energised the telephone line is connected to the remote on-hook detector 5.
• the received pulses are rectified by diode D2 and low pass filtered by R5 and C3 tnen amplified and finally are counted by IC2:A. Because there is one more pulse produced by the circuit than dialled due to the energy in the "end of dialling" spike a count of two pulses is made to signify "1" has been dialled by activating the acoustical signal for "1".
• the binary representation of the count at the output of IC2:A is used to drive a multiplexer, IC3 switching high one of the output Cl to CIO. These outputs form the input to the acoustical signal generator 6.
• a 555 counter generates a 10 kHz pulse stream which is input to counter IC1:A.
• the outputs of this counter will each represent a different acoustical signal.
• One of these signals is coupled via a logic network to the speaker depending upon which output of IC3 is high. Whichever acoustical signal is generated, relay 3 is energised, by combining the signals RL1 ....RL10 in IC1 to IC5 so that whichever is high the output of IC5:A is high.
• relay 3 When relay 3 is energised the acoustical signal is unaffected.
• the opto-coupler PH02 is connected across the line. Because the called party has not yet lifted the hand- set the line is terminated by a 10K resistor in series with the phot ⁇ diode. The dc voltage from the exchange turns on the output transistor of the opto-coupler, causing a low transition at the input to the counter. If the calling party abandons the call the opto-coupler output will go high causing a low-high transition at the counter input and the output at Q7 will go low, causing relay 1 to be de-energised and restoring the telephone line to the ring detect unit 2 ready for the next call. At the same time the pulse detector is reset to a count of zero inhibiting the acoustical signal.
• relay 7 serves to connect the handset to the telephone line once it has been answered.
• micro ⁇ processor could be built into the unit. This would calculate the electrical representation of the secondary code number and assign a value to it. The program would then compare the varying input expression against the constant expressions programmed into the memory. If an assigned value match occurs an instruction is then given to initiate the appropriate part of the program which initiates the recepients or the callers identification sound.
• It may also be capable of distinguishing external and internal calls by sound.
• a mechanism may also be included in the system to provide sound differentiation for each extension phone if used.
• the recipent can choose not to answer unwanted calls .
• the system can be used to prevent crank calls.

Landscapes

• Engineering & Computer Science (AREA)
• Signal Processing (AREA)
• Computer Security & Cryptography (AREA)
• Telephonic Communication Services (AREA)
• Telephone Function (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=3773234

Family Applications (1)

Country Status (4)

Families Citing this family (10)

Family Cites Families (22)

• 1989
  • 1989-04-07 JP JP1504406A patent/JPH03501674A/ja active Pending
  • 1989-04-07 KR KR1019900700622A patent/KR900702695A/ko not_active Withdrawn
  • 1989-04-07 WO PCT/AU1989/000152 patent/WO1990001236A1/en not_active Ceased
  • 1989-04-07 EP EP19890904739 patent/EP0423131A4/en not_active Withdrawn

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