Patent US3965306A successfully refreshed from Google Patents.
US3965306A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone line transfer circuit
Assignee: SAN BAR CORP
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Filing: 1974-11-11
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Granted: 1976-06-22
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Expires: 1994-11-11
Abstract
Abstract Transfer of an incoming call on a first telephone line for a first subscriber set to a second, independent telephone line for a second subscriber set is accomplished without permitting a party at the first subscriber set to listen to the transferred call. An adjustable time delay circuit causes the tip and ring leads of the first central office telephone line to be switched to the second subscriber set, after a predetermined amount of ringing at the first subscriber set. If the second subscriber set is in use or is being rung at the time a transfer is to take place, no switching occurs. If the first subscriber set is answered before the preset time delay is elapsed, no switching occurs. The line transfer circuit may operate from either a -24 or -48 volt DC supply. Upon transfer of the first pair of tip and ring central office lines to the second subscriber set, the second pair of tip and ring central office lines are isolated and terminated with a capacitor suitably chosen to represent a high impedance ringer.
Inventors
- 👤 Arthur Gene Watkins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:21
CPC Classifications
H; H04; H04M; H04M7/00; H04M7/0096; H04M1/00; H04M1/006
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
169 words
A telephone line transfer circuit for transferring a first pair of tip and ring lines, connected between a central office and a first subscriber set, to a second subscriber set, connected to a second pair of tip and ring lines from a central office, said line transfer circuit comprising: first ring current detector means for detecting ringing current in said first pair of tip and ring lines; second ring current detector means for detecting ringing current in said second pair of tip and ring lines; loop current detector means for detecting loop current in said second pair of tip and ring lines; means responsive to said first ring current detector means for, after a predetermined time delay, connecting said first pair of tip and ring lines to said second subscriber set and disconnecting said first subscriber set from said first pair of tip and ring lines; and means responsive to said second ring current detector means or said loop current detector means for preventing said connecting means from operating.
Claim 2
Dependent Claim
169 words
A telephone line transfer circuit for transferring a first pair of tip and ring lines, connected between a central office and a first subscriber set, to a second subscriber set, connected to a second pair of tip and ring lines from a central office, said line transfer circuit comprising: first ring current detector means for detecting ringing current in said first pair of tip and ring lines; second ring current detector means for detecting ringing current in said second pair of tip and ring lines; loop current detector means for detecting loop current in said second pair of tip and ring lines; means responsive to said first ring current detector means for, after a predetermined time delay, connecting said first pair of tip and ring lines to said second subscriber set and disconnecting said first subscriber set from said first pair of tip and ring lines; and means responsive to said second ring current detector means or said loop current detector means for preventing said connecting means from operating.
Claim 3
Dependent Claim
21 words
The telephone line transfer circuit of claim 1 wherein said connecting means includes: means for manually adjusting the predetermined time delay.
Claim 4
Dependent Claim
50 words
The telephone line transfer circuit of claim 1 further comprising: means responsive to said connecting means for disconnecting said second subscriber set from said second pair of tip and ring lines and connecting an impedance representative of a high impedance ringer across said second pair of tip and ring lines.
Claim 5
Dependent Claim
31 words
The telephone line transfer circuit of claim 1 wherein said preventing means disables said connecting means prior to its operation and has no effect on said connecting means after its operation.
Claim 6
Dependent Claim
50 words
The telephone line transfer circuit of claim 1 further comprising: means responsive to said second subscriber set terminating a conversation for reconnecting said first pair of tip and ring lines to said first subscriber set, and reconnecting said second pair of tip and ring lines to said second subscriber set.
Claim 7
Dependent Claim
180 words
A line transfer circuit for transferring a first pair of tip and ring lines, connected to a first subscriber set, to a second subscriber set, connected to a second pair of tip and ring lines, said line transfer circuit comprising: first ring current detector means for detecting ringing current in said first pair of tip and ring lines; first loop current detector means for detecting loop current in said first pair of tip and ring lines; second ring current detector means for detecting ringing current in said second pair of tip and ring lines; second loop current detector means for detecting loop current in said second pair of tip and ring lines; means responsive to said first ring current detector means for, after a predetermined time delay, connecting said first pair of tip and ring lines to said second subscriber set and disconnecting said first subscriber set from said first pair of tip and ring lines; and means responsive to said second ring current detector means or said second loop current detector means for preventing said connecting means from operating.
Claim 8
Dependent Claim
180 words
A line transfer circuit for transferring a first pair of tip and ring lines, connected to a first subscriber set, to a second subscriber set, connected to a second pair of tip and ring lines, said line transfer circuit comprising: first ring current detector means for detecting ringing current in said first pair of tip and ring lines; first loop current detector means for detecting loop current in said first pair of tip and ring lines; second ring current detector means for detecting ringing current in said second pair of tip and ring lines; second loop current detector means for detecting loop current in said second pair of tip and ring lines; means responsive to said first ring current detector means for, after a predetermined time delay, connecting said first pair of tip and ring lines to said second subscriber set and disconnecting said first subscriber set from said first pair of tip and ring lines; and means responsive to said second ring current detector means or said second loop current detector means for preventing said connecting means from operating.
Claim 9
Dependent Claim
20 words
The line transfer circuit of claim 6 wherein said connecting means includes: means for manually adjusting the predetermined time delay.
Claim 10
Dependent Claim
49 words
The line transfer circuit of claim 6, further comprising: means responsive to said connecting means for disconnecting said second subscriber set from said second pair of tip and ring lines and connecting an impedance representative of a high impedance ringer across said second pair of tip and ring lines.
Claim 11
Dependent Claim
25 words
The line transfer circuit of claim 6 further comprising: means responsive to said first loop current detector means for preventing said connecting means from operating.
Claim 12
Dependent Claim
49 words
The line transfer circuit of claim 6 further comprising: means responsive to said second subscriber set terminating a conversation for reconnecting said first pair of tip and ring lines to said first subscriber set, and reconnecting said second pair of tip and ring lines to said second subscriber set.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-22 | 1979-12-22 | 1980-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-22 | 1983-12-22 | 1984-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-22 | 1987-12-22 | 1988-06-22 | $7700.00 | Window Closed / Lapsed |