US3843845A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic key telephone system
Assignee: Nortel Networks Ltd
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Filing: 1972-09-11
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Granted: 1974-10-22
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Expires: 1992-09-11
Abstract
Abstract An electronic key telephone system which utilizes only a single communication line and a single bi-directional control bus between each of a plurality of station sets and a central control unit to provide all services for the system. The system is organized to first transmit an address from the central control unit to a selected station set which is then followed by the transmission of status information from the central control unit to the station set or vice versa. Because of this organization, the system is readily adapted to provide auxiliary services such as computer and information retrieval and display.
Inventors
- 👤 P Ridley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:45
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/002; H04M9/005; H04M9/007
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
306 words
A key telephone system for connection to a plurality of telephone lines, comprising: a plurality of telephone stations each including line selectors corresponding to individual ones of said lines; central switching means and central control means; each of the telephone stations being connected to the central switching means by a single communication path and also being connected to the central control means by a single data path; said central control means including means for periodically transmitting over each of the single data paths an information to follow address or an information request address to a selected one of the telephone stations; said central control means including means responsive to said information to follow address for transmitting central control status information to the selected station, and means responsive to said information request address for receiving station status information from the selected station via said single data path; said central control means also including a memory for storing status information and means responsive to the station status information from said selected station for controlling said central switching means to connect the communications path of said selected station to one of said telephone lines; each of the telephone stations including means for decoding the information to follow address and the information request address, means responsive to the information to follow address for conditioning the station in a receive mode, means responsive to the central control status information transmitted from the central control means for displaying the status at the selected station, and means responsive to said information request address for transmitting the station status information to the central control means over the single data path; and each of the telephone stations also including a switch hook independent of the communication path; and means responsive to the switch hook for transmitting the station status information to the central control means.
Claim 2
Dependent Claim
306 words
A key telephone system for connection to a plurality of telephone lines, comprising: a plurality of telephone stations each including line selectors corresponding to individual ones of said lines; central switching means and central control means; each of the telephone stations being connected to the central switching means by a single communication path and also being connected to the central control means by a single data path; said central control means including means for periodically transmitting over each of the single data paths an information to follow address or an information request address to a selected one of the telephone stations; said central control means including means responsive to said information to follow address for transmitting central control status information to the selected station, and means responsive to said information request address for receiving station status information from the selected station via said single data path; said central control means also including a memory for storing status information and means responsive to the station status information from said selected station for controlling said central switching means to connect the communications path of said selected station to one of said telephone lines; each of the telephone stations including means for decoding the information to follow address and the information request address, means responsive to the information to follow address for conditioning the station in a receive mode, means responsive to the central control status information transmitted from the central control means for displaying the status at the selected station, and means responsive to said information request address for transmitting the station status information to the central control means over the single data path; and each of the telephone stations also including a switch hook independent of the communication path; and means responsive to the switch hook for transmitting the station status information to the central control means.
Claim 3
Dependent Claim
98 words
A key telephone system as defined in claim 1 in which the line selectors are functionally independent momentary actuated switches; and in which each of the line selectors is associated with a respective pair of status lights; each of said telephone stations also including means responsive to the central control status information from the memory for actuating one of the pair of status lights to indicate the status of an individual line at all the stations, and for actuating the other of said pair of status lights to indicate the selection of a line at the same station.
Claim 4
Dependent Claim
99 words
A key telephone system as defined in claim 1 in which each of the telephone stations includes a pushbutton dial having means for encoding its output in the form of a digital output for transmission as station status information over the single data path connected to the respective station; and in which the central control means includes means for generating dial signals on each of said telephone lines, and means for controlling the dial signal generating means of a selected line in response to the station status information received from the digital output of one of the pushbutton dials.
Claim 5
Dependent Claim
38 words
A key telephone system as defined in claim 3 in which the means for encoding includes a pushbutton dial to binary code converter; and in which the central control unit includes a binary code to dial pulse converter.
Claim 6
Dependent Claim
67 words
A key telephone system as defined in claim 1 in which the means for periodically transmitting an information to follow address includes means for transmitting a mode bit to designate subsequent transmission of central control status information to the telephone stations and in which the means for periodically transmitting an information request address includes means to designate subsequent reception of station status information from the telephone stations.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |