Patent US3762152A successfully refreshed from Google Patents.
US3577201A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Portable computer terminal
Assignee: Vernitron Corp
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Filing: 1968-01-08
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Granted: 1971-05-04
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Expires: 1988-01-08
Abstract
Abstract The invention is concerned with a logic decoder means which senses a signal indicative of whether a teletype machine or a computer originates a communicative line between a portable computer terminal and the computer. The modulator and demodulator within the portable terminal computer operate in different frequency bands and have filter networks adapted to be switched into circuit with the information signals, in response to output signals from the logic decoder and thereby set the respective frequency bands in the modulator and demodulator.
Inventors
- 👤 Jesse T Quatse
- 👤 Brook Dixon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:48
CPC Classifications
H; H04; H04L; H04L5/00; H04L5/02; H04L5/06; G; G06; G06F; G06F3/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
229 words
In combination with a portable computer terminal adapted to be coupled via a conventional telephone handset to a distant computer over telephone lines of the type wherein information to be transmitted to said computer is coded in mark space signals by a teletypewriter and then converted to audio frequency signals in a particular frequency band by a modulator means having an input coupled to said teletypewriter and an output coupled to a transmitting portion of said handset and wherein information from said computer is received and converted to coded mark space signals in another frequency band by a demodulator having an input coupled to a receiver portion of said handset and an output coupled to said teletypewriter wherein the improvement comprises: a logic decode means adapted to receive an input originate signal and to provide one of two output control signals to said modulator means and to said demodulator means, said output control signal depending upon whether said originate signal is received from an operator of said portable computer terminal or from said computer whereby said modulator means and said demodulator means will have their different respective frequency bands interchanged upon change of said output control signal, and said modulator means including a filter circuit having a plurality of resistive branches, at least one of which is adapted to be short circuited in response to said output control signals.
Claim 2
Dependent Claim
229 words
In combination with a portable computer terminal adapted to be coupled via a conventional telephone handset to a distant computer over telephone lines of the type wherein information to be transmitted to said computer is coded in mark space signals by a teletypewriter and then converted to audio frequency signals in a particular frequency band by a modulator means having an input coupled to said teletypewriter and an output coupled to a transmitting portion of said handset and wherein information from said computer is received and converted to coded mark space signals in another frequency band by a demodulator having an input coupled to a receiver portion of said handset and an output coupled to said teletypewriter wherein the improvement comprises: a logic decode means adapted to receive an input originate signal and to provide one of two output control signals to said modulator means and to said demodulator means, said output control signal depending upon whether said originate signal is received from an operator of said portable computer terminal or from said computer whereby said modulator means and said demodulator means will have their different respective frequency bands interchanged upon change of said output control signal, and said modulator means including a filter circuit having a plurality of resistive branches, at least one of which is adapted to be short circuited in response to said output control signals.
Claim 3
Dependent Claim
131 words
The combination as recited in claim 1 wherein said demodulator means includes four filter circuits arranged in two sets of two filter units each, one of said sets having one filter tuned to a mark frequency signal for originate signals from said computer and the other filter tuned only to a mark frequency signal for originate signals from said transducer means, the other of said sets having one filter tuned to a space frequency for originate signals from said computer and the other filter tuned only to a space frequency signal for originate signals from said transducer means, and a demodulator mode switch means responsive to said output control signal to connect one filter circuit of each of said sets to provide for separate filtering of said mark and space signals.
Claim 4
Dependent Claim
49 words
The combination as defined in claim 1 including an additional switch filter means in circuit with said demodulator means and having a band width for passing both mark and space signals selectively depending upon whether said originate signal comes from said computer means or from said portable computer operator.
Claim 5
Dependent Claim
42 words
The combination as recited in claim 1 further including a modulator mode switch means comprised of transistors having their emitter-collector paths connected in circuit with said resistive branches and means interconnecting the control electrodes of said transistors to said logic decode means.
Claim 6
Dependent Claim
44 words
The combination as recited in claim 1 including additional switch filter means in circuit with said modulator and having a frequency band width for passing both said mark and space signals respectively, in response to said output control signals from said decode logic means.
References Cited (Backward Citations)
US3226480A
Cited
US3261922A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |