Patent US5355407A successfully refreshed from Google Patents.
US5355407A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phone busy circuit
Assignee: Astro Science Corp
•
Filing: 1992-10-13
•
Granted: 1994-10-11
•
Expires: 2012-10-13
Abstract
Abstract A switching circuit places a load across the TIP and RING signals of a telephone line when the computer is reset and removes the load when the computer accesses a selected memory location. Thus, the telephone line remains in an off-hook state after the computer is reset and remains in that state until the computer executes software that causes the telephone line to return to the on-hook state. The computer may also execute software that causes the telephone line to enter the off-hook state.
Inventors
- 👤 George L. Lazik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:04
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/02; H04L12/10
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
117 words
A circuit for placing a busy signal on a telephone line while a computer is resetting, said telephone line having a TIP signal and a RING signal, said circuit comprising: decoder means for receiving a system address from said computer and for providing a decoder output signal in response to access of a predetermined system address by said computer; memory means for entering a first state in response to a system reset signal received from said computer and for entering a second state in response to said decoder output signal; a resistor; and switching means for connecting said resistor between said TIP signal and said RING signal only when said memory means is in said first state.
Claim 2
Dependent Claim
117 words
A circuit for placing a busy signal on a telephone line while a computer is resetting, said telephone line having a TIP signal and a RING signal, said circuit comprising: decoder means for receiving a system address from said computer and for providing a decoder output signal in response to access of a predetermined system address by said computer; memory means for entering a first state in response to a system reset signal received from said computer and for entering a second state in response to said decoder output signal; a resistor; and switching means for connecting said resistor between said TIP signal and said RING signal only when said memory means is in said first state.
Claim 3
Dependent Claim
15 words
The circuit described in claim 1, further comprising means for selecting said predetermined system address.
Claim 4
Dependent Claim
22 words
The circuit described in claim 2, wherein said means for selecting said predetermined system address comprises at least one address selection jumper.
Claim 5
Dependent Claim
20 words
The circuit described in claim 3, wherein said decoder means comprises a PAL connected to each said address selection jumper.
Claim 6
Dependent Claim
25 words
The circuit described in claim 4, wherein: two said address selection jumpers select said predetermined system address from among four addresses programmed in said PAL.
Claim 7
Dependent Claim
19 words
The circuit described in claim 4, wherein said access comprises a write operation to said selected predetermined system address.
Claim 8
Dependent Claim
26 words
The circuit described in claim 5, wherein said memory means enters said first state in response to a read operation from said selected predetermined decoder address.
Claim 9
Dependent Claim
116 words
A circuit for placing a busy signal on a telephone line while a computer is resetting, said telephone line having a TIP signal and a RING signal, said circuit comprising: a PAL for receiving a system address from said computer and for providing a decoder output signal in response to access of a predetermined system address by said computer; a flip-flop for entering a first state in response to a system reset signal received from said computer and for entering a second state in response to said decoder output signal; a resistor; and an opto-isolator for connecting said resistor between said TIP signal and said RING signal only when said flip-flop is in said first state.
Claim 10
Dependent Claim
116 words
A circuit for placing a busy signal on a telephone line while a computer is resetting, said telephone line having a TIP signal and a RING signal, said circuit comprising: a PAL for receiving a system address from said computer and for providing a decoder output signal in response to access of a predetermined system address by said computer; a flip-flop for entering a first state in response to a system reset signal received from said computer and for entering a second state in response to said decoder output signal; a resistor; and an opto-isolator for connecting said resistor between said TIP signal and said RING signal only when said flip-flop is in said first state.
Claim 11
Dependent Claim
16 words
The circuit described in claim 8, wherein said resistor has a resistance of about 620 ohms.
Claim 12
Dependent Claim
26 words
The circuit described in claim 9, further comprising a jumper for preventing said opto-isolator from connecting said resistor between said TIP signal and said RING signal.
Claim 13
Independent Claim
73 words
A method for placing a busy signal on a telephone line having a TIP signal and a RING signal while a computer is resetting, comprising the steps of: placing a resistor across said TIP signal and said RING signal in response to a RESET signal from a computer; and removing said resistor from across said TIP signal and said RING signal in response to access of a predetermined system address by said computer.
Claim 14
Independent Claim
73 words
A method for placing a busy signal on a telephone line having a TIP signal and a RING signal while a computer is resetting, comprising the steps of: placing a resistor across said TIP signal and said RING signal in response to a RESET signal from a computer; and removing said resistor from across said TIP signal and said RING signal in response to access of a predetermined system address by said computer.
Claim 15
Dependent Claim
29 words
The method for placing a busy signal on a telephone line described in claim 11, further comprising, before said placing step, the step of selecting said predetermined system address.
Claim 16
Dependent Claim
22 words
The method for placing a busy signal on a telephone line described in claim 12, wherein said access is a write operation.
Claim 17
Dependent Claim
46 words
The method for placing a busy signal on a telephone line described in claim 13, wherein said placing step further comprises placing a resistor across said TIP signal and said RING signal in response to a read operation to said predetermined system address by said computer.
References Cited (Backward Citations)
US3858008A
Cited
US4051326A
Cited
US4314103A
Cited
US4759052A
Cited
US5003581A
Cited
US4995074A
Cited
US5086453A
Cited
US5018190A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-10-10 | 1998-04-11 | 1998-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-10-10 | 2002-04-11 | 2002-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-10-10 | 2006-04-11 | 2006-10-11 | $7700.00 | Window Closed / Lapsed |