US4401847A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone communication system
Assignee: Catalyst Research Corp
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Filing: 1980-07-30
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Granted: 1983-08-30
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Expires: 2000-07-30
Abstract
Abstract A multi-wire telephone system which facilitates voice and data communication between any two telephones connected to each other with one of a plurality of standard shielded twisted-pair cables. The telephones, which are battery-powered, feature standard telephone operation without a central switching and control station or PBX. Each telephone is provided with a microprocessor which can generate and decode all signals necessary to establish communication with any other telephone in the system. Since a PBX is not required, a break in any phone line will result in two systems operating independently of each other although somewhat degraded performance can be expected, depending upon the nature of the break. Whenever communication is established between two stations in the system, a direct current bias is impressed on the cable interconnecting those stations such that all other stations in the system can determine that that particular cable is in use and can select another cable for communication. Communication is initially established between stations with the use of frequency shift keyed signals sent from one station and retransmitted from the called station before voice communication is established. The telephone system has both private and page communication capabilities and can transmit data in the form of pulsed signals as well as voice signals. The system incorporates a main dispatcher station which can interrupt any private communication in emergency situations and for data transmission.
Inventors
- 👤 Alan A. Schneider
- 👤 Ronald J. Flower
- 👤 George C. Bowser
- 👤 Lewis C. Kenyon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:48
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/002; H04M11/00; H04M11/06
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
112 words
In a telephone communication system of the type wherein a plurality of stations are adapted to communicate over any one of a plurality of conductors connected to each of the stations without the need for a central switching and control station, the combination of means at each of said stations for establishing communication between it and another station in the system over a selected one of said conductors, and means at each station for impressing a direct current bias on a conductor through which it has established communication with another station such that all other stations in the system will be apprised that a particular conductor interconnecting two stations is in use.
Claim 2
Dependent Claim
112 words
In a telephone communication system of the type wherein a plurality of stations are adapted to communicate over any one of a plurality of conductors connected to each of the stations without the need for a central switching and control station, the combination of means at each of said stations for establishing communication between it and another station in the system over a selected one of said conductors, and means at each station for impressing a direct current bias on a conductor through which it has established communication with another station such that all other stations in the system will be apprised that a particular conductor interconnecting two stations is in use.
Claim 3
Dependent Claim
58 words
The telephone system of claim 1 including means at each of said stations for scanning said plurality of conductors to determine which conductors have a direct current bias thereon, and means, actuable when it is desired to establish communication with another station, for connecting a station to a conductor which does not have a direct current bias thereon.
Claim 4
Dependent Claim
15 words
The telephone system of claim 1 wherein each of said conductors comprises a twisted-pair cable.
Claim 5
Dependent Claim
30 words
The telephone system of claim 1 including a microprocessor at each of said stations for controlling said means for establishing communication and said means for impressing a direct current bias.
Claim 6
Dependent Claim
47 words
The telephone system of claim 4 including a relay matrix under the control of said microprocessor for connecting a selected conductor to said station, said matrix including a plurality of relays each of which is adapted to connect an associated one of said conductors to said station.
Claim 7
Dependent Claim
24 words
The telephone system of claim 5 wherein said microprocessor actuates the relays in said matrix to connect each conductor to a station in sequence.
Claim 8
Dependent Claim
27 words
The telephone system of claim 5 including means for detecting a direct current bias on any conductor when said relay matrix connects the conductor to said station.
Claim 9
Dependent Claim
31 words
The telephone system of claim 4 including means at said station for transmitting a frequency shift keyed signal from that station identifying a station to be called in the communication system.
Claim 10
Dependent Claim
39 words
The telephone system of claim 8 including means at each station in the system for detecting said frequency shift keyed signal, and wherein said microprocessor determines whether said frequency shift keyed signal identifies it as a station being called.
Claim 11
Dependent Claim
16 words
The telephone system of claim 1 wherein communication between stations is by unmodulated audio frequency signals.
Claim 12
Dependent Claim
25 words
The telephone system of claim 10 wherein at least one of said conductors simultaneously carries frequency shift keyed signals as well as audio frequency signals.
Claim 13
Dependent Claim
101 words
In a telephone communication system of the type wherein a plurality of stations are adapted to communicate over any one of a plurality of conductors connected to each of the stations without the need for a central switching and control station, the combination of means at each of said stations for transmitting over one of said conductors a digital signal to all other stations in the system, said digital signal identifying a station to be called and a selected conductor on which it is being called, and means at the station being called for connecting that station to said selected conductor.
Claim 14
Dependent Claim
101 words
In a telephone communication system of the type wherein a plurality of stations are adapted to communicate over any one of a plurality of conductors connected to each of the stations without the need for a central switching and control station, the combination of means at each of said stations for transmitting over one of said conductors a digital signal to all other stations in the system, said digital signal identifying a station to be called and a selected conductor on which it is being called, and means at the station being called for connecting that station to said selected conductor.
Claim 15
Dependent Claim
16 words
The telephone system of claim 12 wherein said digital signal comprises a frequency shift keyed signal.
Claim 16
Dependent Claim
23 words
The telephone system of claim 12 including means at each station for retransmitting to a calling station an echo of said digital signal.
Claim 17
Dependent Claim
41 words
The telephone system of claim 12 wherein each of said stations includes a loud-speaker, and including a page conductor in said plurality of conductors for carrying page audio signals from any station to the loud-speakers of all stations in the system.
Claim 18
Dependent Claim
39 words
The telephone system of claim 12 including means, operable after the station being called is connected to said selected conductor, for transmitting digital data on said selected conductor derived from devices separate from but connected to a calling station.
Claim 19
Dependent Claim
24 words
The telephone system of claim 16 including means at the calling station for accessing, storing and formulating digital data derived from said separate devices.
Claim 20
Dependent Claim
94 words
In a telephone communication system of the type wherein a plurality of stations are adapted to communicate over any one of a plurality of conductors connected to each of the stations without the need for a central switching and control station, the combination of means at each of said stations for establishing communication between it and another station in the system over a selected one of said conductors, a dispatcher station in said system, and means including a microprocessor at said dispatcher station for checking the integrity of every other station in the system.
Claim 21
Dependent Claim
94 words
In a telephone communication system of the type wherein a plurality of stations are adapted to communicate over any one of a plurality of conductors connected to each of the stations without the need for a central switching and control station, the combination of means at each of said stations for establishing communication between it and another station in the system over a selected one of said conductors, a dispatcher station in said system, and means including a microprocessor at said dispatcher station for checking the integrity of every other station in the system.
Claim 22
Dependent Claim
43 words
The telephone system of claim 18 including a microprocessor at each station in the system, and means for transmitting frequency shift keyed signals from the dispatcher station to every other station in the system to check the integrity of said every other station.
References Cited (Backward Citations)
US4188511A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-29 | 1987-02-28 | 1987-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-29 | 1991-02-28 | 1991-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-29 | 1995-02-28 | 1995-08-30 | $7700.00 | Window Closed / Lapsed |