COMBINATION TELEPHONE AND VIDEO COMMUNICATION SYSTEM

• US 3,816,662 A
• Filed: 11/13/1972
• Issued: 06/11/1974
• Est. Priority Date: 11/13/1972
• Status: Expired due to Term

• Current Assignee: AG Communication Systems Corp. (Nokia Corporation)
• Original Assignee: David M. Shaver, Delbert A. Russell
• Inventors: Shaver, David M., Russell, Delbert A.
• Primary Examiner(s): Claffy, Kathleen H.
• Assistant Examiner(s): D'Amico, Thomas
• Application Number:
  US05/306,107
• Time in Patent Office: 575 Days
• Field of Search: 179/2TV,2DP,1CN,1H,18BC 178/DIG.13
• US Class Current: 348/14.11
• CPC Class Codes: H04M 11/025 Door telephones adapted for television H04N7/186
• CPC Class Codes: H04N 7/147 Communication arrangements, e.g. identifying the communication as a video-communication, intermediate storage of the signals selecting H04Q
• CPC Class Codes: H04N 7/186 Video door telephones

Abstract

A door intercom and entrance control system with video facility in which use is made of the telephone line of the desired resident to selectively enable the TV monitor in the called resident'"'"''"'"'s apartment. All TV monitors are served by a coaxial cable terminating in a TV camera at the building entrance, in common. The enabling signal is in the form of a burst of abovespeechband frequency which is transmitted, incident to a call from the entrance, ahead of the first splash of ringing frequency or call-waiting tone, as the case may be. Upon cessation of the enabling signal the signal receiver at the apartment end locks to the video received over the coaxial cable. A guard circuit is provided to prevent false triggering of the TV monitor due to spurious signals received over the telephone line.

Claims

1. A combination telephone and video communication system comprising:

first telephone apparatus and first video terminal apparatus at a predetermined location, a plurality of second telephone apparatus and second video terminal apparatus at a plurality of locations remote from said predetermined location, a plurality of two-wire telephone lines each individual to a corresponding second telephone apparatus for connecting said corresponding second telephone apparatus with said first telephone apparatus, video transmission means distinct from said telephone lines for connecting said second video terminal apparatus with said first video terminal apparatus, selecting means at said predetermined location for selectively extending a call to a desired one of said second telephone apparatus, switching means controlled by said selecting means for transmitting incident to said call, signalling current over the individual two-wire telephone line corresponding to said desired telephone apparatus, and video terminal apparatus control means at each of said remote locations and connected both to the corresponding two-wire telephone line and the corresponding second video terminal apparatus, the control means at the desired remote location being responsive to the receipt of said signalling current over said individual two-wire telephone line to automatically make the video operation of the corresponding video terminal apparatus effective.

2. A combination telephone and video communication system as claimed in claim 1, wherein said plurality of second video terminal apparatus are connected to said video transmission line in common.

3. A combination telephone and video communication system as claimed in claim 2, wherein said switching means are effective to first transmit an enabling signal of above-speechband frequency and then an inband calling signal over said individual two-wire telephone line, and wherein said control means include detector means tuned to the frequency of and responsive to said enabling signal.

4. A combination telephone and video communication system as claimed in claim 3, wherein said enabling signal is of a frequency corresponDing to the horizontal oscillator frequency of the video system.

5. A combination telephone and video communication system as claimed in claim 3, wherein said first video terminal apparatus is a TV camera dnd said second video terminal apparatus are TV monitors, and wherein said switching means include means for switching the video output signal of said camera through to said common video transmission line.

6. A combination telephone and video communication system as claimed in claim 5, wherein said control means also comprise circuit means activated under the control of said video signal, when received after the receipt over said telephone line of said enabling signal, for holding said TV monitor, subsequent to the cessation of said enabling signal, in its activated state for the duration of said video signal.

7. A combination telephone and video communication system as claimed in claim 6, wherein said control means comprise guard means for inhibiting the enabling of said monitor in response to the receipt of a spurious signal of said above-speechband frequency if a signal of said frequency is received over said telephone line only subsequent to the receipt of said video signal over said transmission line.

8. An apartment building intercom system comprising, in separate apartments of said building, a plurality of telephone substations and a plurality of TV monitors, a plurality of separate two-wire central office subscriber lines for said substations, an intercom station and a TV camera at an entrance to said building, an intercom line terminated by said intercom station, a video transmission line common to said plurality of monitors for connecting said plurality of monitors with said camera, manually operable means at said intercom station for selecting one of said substations, switching means defining a point of juncture between each of said two-wire subscriber lines and said intercom line and permitting each said subscriber line to be divided into a substation section and a central office section, said switching means including:

means for supervising said two-wire subscriber lines, means jointly controlled by said manually operable means and said supervisory means for causing an inband calling signal to be transmitted over said substation section for signalling the selected substation and, prior to the transmission of said inband calling signal, also causing an enabling signal of above-speechband frequency to be transmitted over said substation section, and monitor control means at each said substation and connected both to the substation section of its corresponding two-wire line and the corresponding monitor, the control means at said selected substation being responsive to the receipt of said enabling signal to automatically activate, and display the picture at, the monitor corresponding to said selected substation.

9. An apartment building intercom system as claimed in claim 8, wherein said monitors are of the instant-on picture type.

10. An apartment building intercom system comprising, in separate apartments of said building, a plurality of telephone substations and a plurality of TV monitors of the instant-on picture type, a plurality of separate two-wire central office subscriber lines for said substations, an intercom station and a TV camera at an entrance to said building, an intercom line terminated by said intercom station, a video transmission line common to said plurality of monitors for connecting said plurality of monitors for connecting said plurality of monitors with said camera, manually operable means at said intercom station for selecting one of said substations, switching means defining a point of juncture between each of said two-wire subscriber lines and said intercom line and permitting each said subscriber line to be divided into a substation section and a central office section, said switching means including:

means for supervising said two-wire subscriber lines, means jointly controlled by said manually operable means and said supervisory means and including means effective, if said selected two-wire line is idle, to transfer the substation section of the selected two-wire line from the respective central office section to said intercom line, and to cause to be transmitted over said substation section first a burst of enabling signal current of above-speechband frequency and then inband ringing current for signalling the selected substation, and monitor control means at each said substation and connected both to the substation section of its corresponding two-wire line and the corresponding monitor, the control means at said selected substation being effective upon receipt of said enabling signal to activate the monitor corresponding to said selected substation, whereby the resident upon viewing the picture on the monitor, is provided with the option of leaving the telephone call unanswered if desired.

11. An apartment building intercom system as claimed in claim 9 wherein said jointly controlled means include means effective if the selected two-wire line is busy, to first cause a burst of enabling signal current to be transmitted over said substation section and, simultaneously therewith, a holding bridge to be connected across said central office section, and then cause a call waiting tone to be transmitted over said substation section.

12. An apartment building intercom system as claimed in claim 8, wherein said building has a plurality of entrances;

wherein an intercom station, manually operable means and a TV camera are provided at each said entrance; and

wherein there are provided means effective according to the identity of the intercom station from which a call to one of said substations has been originated, for selectively connecting the TV camera at the originating entrance to said video transmission line.

13. An apartment building intercom system as claimed in claim 12, wherein said TV cameras are continuously operating.

14. An apartment building intercom system as claimed in claim 8 wherein said common video transmission line is a single coaxial cable serving a plurality of floors of said building.