US3647980A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switching network control without network map
Assignee: AT&T Inc
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Filing: 1970-05-07
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Granted: 1972-03-07
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Expires: 1990-05-07
Abstract
Abstract A key telephone system is disclosed in which switching functions are carried out in a central switching network instead of at the telephone set to reduce the amount of cabling in the system. The network is controlled by a central processor without requiring a network map in memory. The network contains fewer cross-points than the product of the number of stations and lines and means are provided to select a special trunk when an attempt is made to operate a nonexistent cross-point at the ''''intersection'''' of the desired station and line.
Inventors
- 👤 Lucian Philip Fabiano Jr
- 👤 John Paul Grandmaison
- 👤 William Wallace Greason
- 👤 Ted R King Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:03
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/42; H04Q3/54; H04Q3/545; H04M; H04M9/00; H04M9/002; H04M9/005; H04M9/007
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
118 words
A telephone switching system having a plurality of key telephone station sets and telephone lines comprising a switching network having direct cross-points for interconnecting certain of said station sets and telephone lines, a plurality of trunks each equipped with network cross-points for lines and stations not having an interconnecting one of said direct cross-points in said network, network control means operable normally to select and operate the cross-point at the intersection of a desired line and station in said network, means for detecting when no cross-point is operated at said intersection, and means controlled by said detecting means for selecting one of said plurality of trunks to interconnect said desired one of said telephone stations and telephone lines.
Claim 2
Dependent Claim
118 words
A telephone switching system having a plurality of key telephone station sets and telephone lines comprising a switching network having direct cross-points for interconnecting certain of said station sets and telephone lines, a plurality of trunks each equipped with network cross-points for lines and stations not having an interconnecting one of said direct cross-points in said network, network control means operable normally to select and operate the cross-point at the intersection of a desired line and station in said network, means for detecting when no cross-point is operated at said intersection, and means controlled by said detecting means for selecting one of said plurality of trunks to interconnect said desired one of said telephone stations and telephone lines.
Claim 3
Dependent Claim
75 words
A telephone switching system according to claim 1 wherein said network control means is normally effective to select said cross point by marking said desired line and said desired station, wherein each of said trunks is equipped with a pair of cross points, and wherein said means for selecting said one of said trunks includes means for marking one of said pair of cross points with which one of said plurality of trunks is equipped.
Claim 4
Dependent Claim
43 words
A telephone switching system according to claim 2 wherein said means controlled by said detecting means further inCludes means for reoperating said network control means to mark the other of said pair of network cross-points with which said plurality of trunks is equipped.
Claim 5
Dependent Claim
59 words
A telephone switching system according to claim 3 wherein said network control means includes a transistor circuit for providing an enabling current path to a cross point in said network, means for biasing said transistor to the saturated state before said cross point is operated, and means for biasing said transistor to the constant-current state after said cross-point operates.
Claim 6
Dependent Claim
135 words
A key telephone system including a plurality of key telephone station sets, telephone lines, a switching network in which said sets and lines are given appearances, a plurality of cross points in said network for interconnecting certain of said sets and lines, a processor for controlling said network, and a trunk path having a cross point appearance for each line and station in said network, said processor having: first logic means operable to mark one of said station sets and one of said lines'' appearances in said network when a line and station are to be interconnected, second logic means operable to monitor cross point current after said marking, and third logic means operable to simultaneously mark said line, station set and trunk appearances when said monitoring indicates no cross-point current following said first-mentioned marking.
Claim 7
Dependent Claim
135 words
A key telephone system including a plurality of key telephone station sets, telephone lines, a switching network in which said sets and lines are given appearances, a plurality of cross points in said network for interconnecting certain of said sets and lines, a processor for controlling said network, and a trunk path having a cross point appearance for each line and station in said network, said processor having: first logic means operable to mark one of said station sets and one of said lines'' appearances in said network when a line and station are to be interconnected, second logic means operable to monitor cross point current after said marking, and third logic means operable to simultaneously mark said line, station set and trunk appearances when said monitoring indicates no cross-point current following said first-mentioned marking.
Claim 8
Dependent Claim
45 words
A key telephone system according to claim 5 wherein said processor includes further logic means operable to monitor said cross-point current after said line and said station and said trunk marking to ascertain whether a cross point connection has been effected in said switching network.
Claim 9
Dependent Claim
34 words
A key telephone system according to claim 5 wherein said processor includes further logic means for removing said line and said station marking responsive to said monitor logic means detecting said cross-point current flowing.
Claim 10
Dependent Claim
117 words
A telephone switching system comprising a plurality of lines, a plurality of stations, a plurality of current conductable cross-point connecting means fewer in number than the minimum number capable of connecting each of said lines with any of said stations, control means for controlling said connecting means to connect a designated station to a designated line, means for detecting failure of current flow through any cross-point between said designated station and line incident to said control means failing to establish the connection between said designated station and said designated line, and means controlled by said detecting means for establishing an alternate connection between said designated station and said designated line independent of said plurality of connecting means.
Claim 11
Dependent Claim
117 words
A telephone switching system comprising a plurality of lines, a plurality of stations, a plurality of current conductable cross-point connecting means fewer in number than the minimum number capable of connecting each of said lines with any of said stations, control means for controlling said connecting means to connect a designated station to a designated line, means for detecting failure of current flow through any cross-point between said designated station and line incident to said control means failing to establish the connection between said designated station and said designated line, and means controlled by said detecting means for establishing an alternate connection between said designated station and said designated line independent of said plurality of connecting means.
Claim 12
Dependent Claim
34 words
A telephone switching system in accordance with claim 8 wherein said means for establishing said alternate connection includes trunk means and cross point means interconnecting said trunk means to said stations and said lines.
Claim 13
Dependent Claim
77 words
A telephone switching system in accordance with claim 9 wherein said means for establishing said alternate connection includes trunk means, cross point means operable for interconnecting said trunk means with said stations and said lines, and means for simultaneously causing said control means to attempt to establish a connection between said designated station and said designated line and for operating said last-mentioned cross-point means to connect said designated line and said designated station to said trunk means.
Claim 14
Dependent Claim
87 words
A key telephone system including a plurality of line packages, a plurality of station packages, network means including cross-points for interconnecting certain of said line and station packages, separate connecting means including cross-points connected to each of said line and station packages, and means responsive to said network means attempting but failing to establish a connection between one of said line packages and one of said station packages for establishing a connection between said one line package and said one station package by said separate connecting means.
Claim 15
Dependent Claim
87 words
A key telephone system including a plurality of line packages, a plurality of station packages, network means including cross-points for interconnecting certain of said line and station packages, separate connecting means including cross-points connected to each of said line and station packages, and means responsive to said network means attempting but failing to establish a connection between one of said line packages and one of said station packages for establishing a connection between said one line package and said one station package by said separate connecting means.
Claim 16
Dependent Claim
71 words
A key telephone system in accordance with claim 11 further including means for marking said network means to cause one of said network means cross points to establish a connection through said network means between said one line package and said one station package, said means for establishing said connection by said separate connecting means including additional means for simultaneously marking said separate connecting means cross-points and said network means cross-points.
Claim 17
Dependent Claim
44 words
A key telephone system in accordance with claim 12 wherein said means for establishing said connection by said separate connecting means includes means for detecting the absence of current flow through said network means between said one line package and said one station package.
Claim 18
Dependent Claim
91 words
In a telephone system, a plurality of line packages and a plurality of station packages, network means including cross-points for establishing connections between certain of said line packages and said station packages, and means responsive to the attempt to establish a connection by a nonexistent cross-point between a particular station package and a particular line package for establishing a distinct connection between said particular station package and said particular line package, said last mentioned means including trunk means including cross points connected to each of said station packages and line packages.
Claim 19
Dependent Claim
91 words
In a telephone system, a plurality of line packages and a plurality of station packages, network means including cross-points for establishing connections between certain of said line packages and said station packages, and means responsive to the attempt to establish a connection by a nonexistent cross-point between a particular station package and a particular line package for establishing a distinct connection between said particular station package and said particular line package, said last mentioned means including trunk means including cross points connected to each of said station packages and line packages.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-07 | 1975-09-06 | 1976-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-07 | 1979-09-06 | 1980-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-07 | 1983-09-06 | 1984-03-07 | $7700.00 | Window Closed / Lapsed |