CA2070740A1 - Door intercom sharing existing wiring and telephone sets - Google Patents

Door intercom sharing existing wiring and telephone sets

Info

Publication number
CA2070740A1
CA2070740A1 CA 2070740 CA2070740A CA2070740A1 CA 2070740 A1 CA2070740 A1 CA 2070740A1 CA 2070740 CA2070740 CA 2070740 CA 2070740 A CA2070740 A CA 2070740A CA 2070740 A1 CA2070740 A1 CA 2070740A1
Authority
CA
Canada
Prior art keywords
door
intercom
telephone
door bell
intercom system
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
CA 2070740
Other languages
French (fr)
Inventor
Robert H. Patrick
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to CA 2070740 priority Critical patent/CA2070740A1/en
Publication of CA2070740A1 publication Critical patent/CA2070740A1/en
Abandoned legal-status Critical Current

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Landscapes

  • Interconnected Communication Systems, Intercoms, And Interphones (AREA)
  • Sub-Exchange Stations And Push- Button Telephones (AREA)

Abstract

ABSTRACT

The present invention relates to intercom systems, and more particularly to an intercom system where one station is located on the outside of a dwelling adjacent to an entry door and all other stations are the existing telephone sets which prior to embodying the invention where in the sole use of being part of the telephone company network.
Door intercom systems have become increasingly popular as a form of security and convience when responding to the activitation of a "door bell" While such systems operate very well , a significant detracting factor in their use is the installation costs and number of stations in the dwelling.
In this invention the wiring currently in use by the door bell button is re-assigned to the intercom as are the telephone sets and their associated wiring in the dwelling.

Description

-` 2~707~0 SP~CI~C~TIO~

The invention relates to a door intercom.
It is common in door intercom systcms to have one station located a the door, and another located in the dwelling. The installation requires the physical installation of at least two intercom stations and the associated wiring. The costs involved for both interconnecting wire, the additional intercom stations and the installation has restricted the number of intercom stations and their usefulness.
I have found that these disadvantages may be overcomeby re-assigning the wirir.g currently in a dwelling to the intercom system either on a permanent basis as the invention does with regards to the wires to the door bell ~utton, or on a time shared basis 2S
the inverLtion does with rcgards to the use of telephone sets and their wirin~ in the dw~lling.
The invention allows the user to respond to the sound of a door bell by lifting any telephone hand set off its cradle and speaking through it to the telephone set located at the door adjacent to the door bcll button pressed. Provision has been provided to maintain the normal operation of the telephone set for normal telephony use, and also to allow the user to respond to a daor be~l thou~h the telephone may at that time be in use.

Referring to the accompanying drawings, and especially to figure 1, there is illustrated an intercom system that includes a door station 1, a door bell button 2, a door bell 4, telephone sets 3, telephone company wires 7, control unit 6 and a power source 5. The door bell repacement switch 8 is also shown as are the door bell wires 9 and the telephone set extension wires 10.

The installation of the invention requires the user to remove the door bell button 2, from its associated wires 9 and connect those same wires 9 to the door intercom unit. The door bell wires 9 are then cut, with the wires now connected to the door intercom unit extended to connect to the control unit 6 connectors 48. The remaining wires are also extended to connect to the control unit 6, connectors 52.
The telephone company wires 7 are also cut and the wires from the telephone company are connected to the control unit 6 connectors 49. The telephone wires from the dwelling 10 are connected to the control unit 6 connectors 50. A 16 vac power supply 5 is connected to the control unit 6 connectors 51. As the invention logic dictates, the telephones sets 3 are timeshared with the telephone company lines 7 and the door intercom 1.

20707~a Re~erring to figure 2 the functions of the invention are illustrated. When there is no power at 51 or there has been no closing of the door bell button switch, the line relay 18 is as shown, connecting the telephone company wires to the telephone sets 3.
The operation of the invention depends on four conditions.
In the first condition, all telephone sets 3 are on hook and the door bell button switch is closed. The causes the voltage on the connector 48 to go to low, which in turn cause the output of the inverter 53 to go high which in turn causes the latch 41 to be triggered. The Q output of the latch goes high and is connected to the and gate 21. The other input of the and gate 21 is high, causing its output to go high. This output is connected to the trigger input of latch 26 and its output goes high. The output of the latch 26 drives the relay 18, putting the extension phones into the door intercom circuit, removing them fro~q the telephone circuit and allowing two way communications between the door intercom unit 1 and any telephone e~tension 3. At the end of the converstation in the intercom mode, the telephone set 3 is returned on hook. This causes the output of the opto-isolator 17 to go high, which is inverted by 19 and fed to the pulse generating circuit 40 causing a positive pulse at the output of the inverter 23 which inturn is connected to the reset input of latch 26 causing the relay 18 to deenergize connecting the telephone sets 3 to the telephone company line 7.
A second condition is when a ringing signal is sent by the telephone company to the home, while the controller 6 is in intercom mode and a telephone set 3 is off hook. ~ ring generator 29 ca~ses an osclllation to appear between pins 2 and 7 which are connected through a res~stor capacitor path to the primay winding of transformer 31. The secondary of transformer ~l is connected in series with the primary of transfor~:er 30 which in turn is in the current loop of the intercom circuit. This causes a electronic telephone ringing sound to be imposed on the intercom circuit and is heard by the user signalling l:he user that someone is phoning him. T~.e user can now terminate the call by putting his phone on-hook, which causes current through the opto-isolator 17 .o drop to zero, which in turn causes the voltage at pin 5 of 17 to go to logic high, which is inverte,d by 19, and provides a negative pulse from thle resistor capacitor circuit ~0 inverted by 23 providing a negative going pulse at an input of the and gate 22. The other input frGm latch 41 is high having been reset when the phone when off-hook in response to the door bell. The output of 22 is fed via diode 24 to the reset input of latch 26 causing the relay 18 to de-energize with its contacts connecting the telephone sets 3 to the telephone line 49.

20707~

A Lhird condiLion is if the telepholle sets are in normal use connected to the telephone lines 7 anci the door bell rings. In this case, the user would terlDinate the call. With any telephone set 3 off hook current passes through the opto-isolator 17 causing the output pin 5 to go low, this low is inverted by 19, and inverted again by 20 providing a low to an input of the and gate 21. With one input of the and gate 21 low, its output remains low and therefore the latch 26 is not triggered. Latch 41 being triggered by the door bell has its output high going to one input of the and gate 4. When the user is ready to respond to the door bell, the telephone 3 is put on hook~ which inturn causes the opto-isolator 17 output on pin 5 to go high, which is inverted by 19 and 2~) putting a high on one input of the and gate 21, which has a higll on i-~s other input causing its output to go high which in~urn triggers the latch 26 which in turn causes the relay 18 ,o be activated which in turn puts the telephone sets 3 in the intercom circuit. At the completion of the communication with the door intercom, the telephone set 3 is returned to the on hook condition, causing the output of the opto isolator 17 to go high, which is inverted by 19 a low at the pulse generating circuit 40 causing a positive pulse at the output of the inverter 22 which is fed via diode 24 to the reset of latch 26, causing relay 18 to deenergize returning the telephone sets 3 to the telephone line 7.
The forth condition appears when the door bell button switch is closed, and the telephone sets are on-hook putting the controller in the intercom mode. If the telephone set 3 is not put off-hook the system will remain in the intercom mode until a the ringing singal is received from the telephone company, or a telephone set 3 is taken off hook and returned to the on hook condition. When a telephone company ringing sienal is received, the ring detector 29 provide a current to the opto-isolator 28 which causes its output to go low. This output is connected to the inverter 33 which provides a high to the and gate 34, its other input beir~g high because the telephone sets 3 are on hook. The resulting high at the 6 output of the and gate 34 goes to the reset inputs of latches 26 and 41 via doides 25 and 36~ With both latches 25 and 36 reset the relay is denergized connecting the telephone sets to the telephone company lin~ 7.
One general eondition appears every time a telephone set 3 goes off hook. The opto-isolator 17 output goe low which is inverted by the inverter l9 and inverter 19 output is inverted by inverter 20 causing a low to be connected to the pulse generator 39 which causes a positive pulse at the output of inverter 35 which resets the latch 41 via diode 37. A second general condition occurs every time the door bell button 8 is closed. The low created at connector 48 causes a high at the output of the inverter 53 which in turn causes relay 43 to energize closing its contacts which causes the door bell to sound as long as door bell button 8 is pressed.

Claims (7)

1. An intercom system that re-assigns existing wiring now used to connect a door bell button to a door bell circuit and existing telephone sets and their wiring to provide intercom stations in the door intercom system.
2. A signaling circuit that provides power, switch closure information and two way audio on a two wire circuit.
3. A door intercom system that provides automatic switching between door intercom and regular telephony circuits dependant on the door bell being pressed, the on-hook condition of the telephone sets used in the circuit and whether a call is being signalled to the home.
4. A door intercom system that provides full audio duplex operation with the same number of intercom stations as can be connected within the telephone company restraints for the extensions themselves connected to the telephone company lines.
5. A door intercom system using existing telephones with a signalling means to advise the user, if in the intercom mode that someone is phoning their telephone number.
6. A door intercom system using existing telephones that provides for the transfer to intercom mode at the completition of a telephone conversation should the telephone be in use when the door bell is sounded
7. A door intercom system that is automatically reset to normal telephone mode if a call is received and the pressing of a door bell previously put the system in door intercom mode, but had yet to be responded to.
CA 2070740 1992-06-08 1992-06-08 Door intercom sharing existing wiring and telephone sets Abandoned CA2070740A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA 2070740 CA2070740A1 (en) 1992-06-08 1992-06-08 Door intercom sharing existing wiring and telephone sets

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA 2070740 CA2070740A1 (en) 1992-06-08 1992-06-08 Door intercom sharing existing wiring and telephone sets

Publications (1)

Publication Number Publication Date
CA2070740A1 true CA2070740A1 (en) 1993-12-09

Family

ID=4149985

Family Applications (1)

Application Number Title Priority Date Filing Date
CA 2070740 Abandoned CA2070740A1 (en) 1992-06-08 1992-06-08 Door intercom sharing existing wiring and telephone sets

Country Status (1)

Country Link
CA (1) CA2070740A1 (en)

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Legal Events

Date Code Title Description
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