AT&T Inc
AT&T IncActive Patents
0
Total Holdings
224
Patent Holdings
Filter in Explorer →| Patent No. | Title | Status | Filing Date | Grant Date | Claims | Actions |
|---|---|---|---|---|---|---|
| US4412123A | Laminated electric heat generating member for reflow solder… | Expired / Lapsed | 1980-05-09 | 1983-10-25 | 7 | Details |
| US4034347A | Method and apparatus for controlling a multiprocessor system | Expired / Lapsed | 1975-08-08 | 1977-07-05 | 34 | Details |
| US3979733A | Digital data communications system packet switch | Expired / Lapsed | 1975-05-09 | 1976-09-07 | 18 | Details |
| US3793541A | Optical stimulated emission devices employing optical guidi… | Expired / Lapsed | 1970-12-21 | 1974-02-19 | 35 | Details |
| US3770350A | Method utilizing an optical fiber raman cell | Expired / Lapsed | 1972-07-24 | 1973-11-06 | 6 | Details |
| US3718781A | Integrity check equipment for automatic trunk substitution | Expired / Lapsed | 1971-12-30 | 1973-02-27 | 0 | Details |
| US3717850A | Programmed data processing with facilitated transfers | Expired / Lapsed | 1972-03-17 | 1973-02-20 | 80 | Details |
| US3673335A | Switching of time division multiplex lines and analog trunk… | Expired / Lapsed | 1970-08-24 | 1972-06-27 | 11 | Details |
| US3652993A | Rapid polling method for digital communications network | Expired / Lapsed | 1970-07-24 | 1972-03-28 | 13 | Details |
| US3573381A | Time division switching system | Expired / Lapsed | 1969-03-26 | 1971-04-06 | 26 | Details |
| US3573745A | Group queuing | Expired / Lapsed | 1968-12-04 | 1971-04-06 | 17 | Details |
| US3553606A | System for providing adjusting signals to a transversal fil… | Expired / Lapsed | 1969-04-21 | 1971-01-05 | 0 | Details |
| US3553654A | Fault isolation arrangement for distributed logic memories | Expired / Lapsed | 1969-03-28 | 1971-01-05 | 0 | Details |
| US3543243A | Data receiving arrangement | Expired / Lapsed | 1967-09-13 | 1970-11-24 | 0 | Details |
| US3520055A | Method for holding workpieces for radiant energy bonding | Expired / Lapsed | 1967-04-26 | 1970-07-14 | 0 | Details |
| US3488440A | Timing wave recovery circuit for synchronous data repeater | Expired / Lapsed | 1966-12-28 | 1970-01-06 | 0 | Details |
| US3477043A | Automatic d.c. offset compensation circuit for automatic eq… | Expired / Lapsed | 1968-01-24 | 1969-11-04 | 0 | Details |
| US3446917A | Time division switching system | Expired / Lapsed | 1965-06-07 | 1969-05-27 | 0 | Details |
| US3403340A | Automatic mean-square equalizer | Expired / Lapsed | 1966-11-21 | 1968-09-24 | 2 | Details |
| US3403383A | Integrated analog-digital switching system with modular mes… | Expired / Lapsed | 1964-05-28 | 1968-09-24 | 0 | Details |
| US3394355A | Information storage timing arrangement | Expired / Lapsed | 1966-04-15 | 1968-07-23 | 2 | Details |
| US3391390A | Information storage and processing system utilizing associa… | Expired / Lapsed | 1964-09-09 | 1968-07-02 | 0 | Details |
| US3384814A | Ridge waveguide resonant cavity for measuring dielectric co… | Expired / Lapsed | 1963-09-25 | 1968-05-21 | 2 | Details |
| US3376555A | Two-dimensional associative memory system | Expired / Lapsed | 1965-06-18 | 1968-04-02 | 0 | Details |
| US3375473A | Automatic equalizer for analog channels having means for co… | Expired / Lapsed | 1965-07-15 | 1968-03-26 | 2 | Details |
| US3374435A | Reduction of the effect of impulse noise bursts | Expired / Lapsed | 1965-07-29 | 1968-03-19 | 1 | Details |
| US3372244A | Semiconductive transducers | Expired / Lapsed | 1966-07-07 | 1968-03-05 | 0 | Details |
| US3370274A | Data processor control utilizing tandem signal operations | Expired / Lapsed | 1964-12-30 | 1968-02-20 | 0 | Details |
| US3368168A | Adaptive equalizer for digital transmission systems having … | Expired / Lapsed | 1965-06-02 | 1968-02-06 | 2 | Details |
| US3366931A | Information storage system | Expired / Lapsed | 1965-03-23 | 1968-01-30 | 0 | Details |
| US3360610A | Bandwidth compression utilizing magnitude and phase coded s… | Expired / Lapsed | 1964-05-07 | 1967-12-26 | 2 | Details |
| US3344349A | Apparatus for analyzing the spectra of complex waves | Expired / Lapsed | 1963-10-07 | 1967-09-26 | 0 | Details |
| US3334183A | Teletypewriter receiver for receiving data asynchronously o… | Expired / Lapsed | 1963-10-24 | 1967-08-01 | 2 | Details |
| US3315171A | Digitalized transversal filter | Expired / Lapsed | 1963-12-24 | 1967-04-18 | 1 | Details |
| US3292110A | Transversal equalizer for digital transmission systems wher… | Expired / Lapsed | 1964-09-16 | 1966-12-13 | 2 | Details |
| US3291913A | Telephone system signal converter | Expired / Lapsed | 1963-05-17 | 1966-12-13 | 2 | Details |
| US3277225A | Methods and apparatus for multiple extrusion of plastics | Expired / Lapsed | 1963-02-13 | 1966-10-04 | 2 | Details |
| US3242470A | Automation of telephone information service | Expired / Lapsed | 1962-08-21 | 1966-03-22 | 2 | Details |
| US3233112A | Preference circuit employing magnetic elements | Expired / Lapsed | 1960-02-04 | 1966-02-01 | 2 | Details |
| US3188639A | Satellite stabilization and attitude control | Expired / Lapsed | 1961-09-29 | 1965-06-08 | 2 | Details |
| US3185965A | Information storage system | Expired / Lapsed | 1962-04-30 | 1965-05-25 | 1 | Details |
| US3169245A | Passive repeaters for satellite communication systems | Expired / Lapsed | 1959-05-15 | 1965-02-09 | 1 | Details |
| US3164728A | Magnetic switching circuit | Expired / Lapsed | 1962-03-30 | 1965-01-05 | 2 | Details |
| US3136861A | Pcm network synchronization | Expired / Lapsed | 1962-10-18 | 1964-06-09 | 2 | Details |
| US3121255A | Apparatus for extruding plastic compounds | Expired / Lapsed | 1960-11-18 | 1964-02-18 | 1 | Details |
| US3106698A | Parallel data processing apparatus | Expired / Lapsed | 1958-04-25 | 1963-10-08 | 2 | Details |
| US3100868A | Light gas detector using thin walled glass tubes for diffus… | Expired / Lapsed | 1958-08-20 | 1963-08-13 | 2 | Details |
| US3065636A | Pressure transducers | Expired / Lapsed | 1960-05-10 | 1962-11-27 | 0 | Details |
| US3053134A | Optical pulse echo system | Expired / Lapsed | 1948-04-01 | 1962-09-11 | 0 | Details |
| US3042751A | Pulse transmission system | Expired / Lapsed | 1959-03-10 | 1962-07-03 | 0 | Details |
| US3037068A | Retractile tinsel cordage | Expired / Lapsed | 1959-05-04 | 1962-05-29 | 0 | Details |
| US3034345A | Gauges using piezoresistive elements | Expired / Lapsed | 1959-05-19 | 1962-05-15 | 0 | Details |
| US3030609A | Data storage and retrieval | Expired / Lapsed | 1957-10-11 | 1962-04-17 | 0 | Details |
| US3020525A | Record controlled translator | Expired / Lapsed | 1958-04-04 | 1962-02-06 | 0 | Details |
| US3011151A | Signal comparison system | Expired / Lapsed | 1956-04-27 | 1961-11-28 | 0 | Details |
| US2986723A | Synchronization in a system of interconnected units | Expired / Lapsed | 1960-02-26 | 1961-05-30 | 0 | Details |
| US2977575A | Cryotron circuits | Expired / Lapsed | 1957-02-15 | 1961-03-28 | 0 | Details |
| US2969216A | Clamps for securing and supporting articles | Expired / Lapsed | 1958-04-25 | 1961-01-24 | 0 | Details |
| US2969419A | Retractile cords | Expired / Lapsed | 1954-09-07 | 1961-01-24 | 0 | Details |
| US2951229A | Error-detecting and correcting system | Expired / Lapsed | 1959-04-27 | 1960-08-30 | 0 | Details |
| US2951235A | Statistical data accumulator | Expired / Lapsed | 1958-01-15 | 1960-08-30 | 0 | Details |
| US2951240A | Magnetic core circuit | Expired / Lapsed | 1956-10-16 | 1960-08-30 | 0 | Details |
| US2936380A | Light valve logic circuits | Expired / Lapsed | 1955-12-07 | 1960-05-10 | 0 | Details |
| US2935569A | Time assignment speech interpolation system | Expired / Lapsed | 1957-09-26 | 1960-05-03 | 0 | Details |
| US2929922A | Masers and maser communications system | Expired / Lapsed | 1958-07-30 | 1960-03-22 | 0 | Details |
| US2924666A | Telephone system calling stations identifier | Expired / Lapsed | 1957-09-19 | 1960-02-09 | 0 | Details |
| US2898477A | Piezoelectric field effect semiconductor device | Expired / Lapsed | 1955-10-31 | 1959-08-04 | 0 | Details |
| US2892888A | Digital system with error elimination | Expired / Lapsed | 1958-02-10 | 1959-06-30 | 0 | Details |
| US2858524A | Recording scanner | Expired / Lapsed | 1953-11-13 | 1958-10-28 | 0 | Details |
| US2855524A | Semiconductive switch | Expired / Lapsed | 1955-11-22 | 1958-10-07 | 0 | Details |
| US2850650A | Transistor current limiter | Expired / Lapsed | 1956-03-29 | 1958-09-02 | 0 | Details |
| US2828362A | Digit data transmission system | Expired / Lapsed | 1956-01-24 | 1958-03-25 | 0 | Details |
| US2824228A | Pulse train modification circuits | Expired / Lapsed | 1954-12-30 | 1958-02-18 | 0 | Details |
| US2791759A | Semiconductive device | Expired / Lapsed | 1955-02-18 | 1957-05-07 | 2 | Details |
| US2789267A | System for testing pulse generators | Expired / Lapsed | 1953-05-26 | 1957-04-16 | 0 | Details |
| US2775727A | Digital to analogue converter with digital feedback control | Expired / Lapsed | 1954-12-08 | 1956-12-25 | 0 | Details |
| US2774872A | Phase shifting circuit | Expired / Lapsed | 1952-12-17 | 1956-12-18 | 0 | Details |
| US2764642A | Semiconductor signal translating devices | Expired / Lapsed | 1952-10-31 | 1956-09-25 | 0 | Details |
| US2761909A | Multifrequency oscillator | Expired / Lapsed | 1953-01-28 | 1956-09-04 | 0 | Details |
| US2758787A | Serial binary digital multiplier | Expired / Lapsed | 1951-11-27 | 1956-08-14 | 0 | Details |
| US2758788A | Binary code translator, adder, and register | Expired / Lapsed | 1951-11-10 | 1956-08-14 | 0 | Details |
| US2754368A | Telephone system | Expired / Lapsed | 1952-05-03 | 1956-07-10 | 0 | Details |
| US2723312A | Magnetic drum dial pulse recording and storage registers | Expired / Lapsed | 1954-09-15 | 1955-11-08 | 0 | Details |
| US2717373A | Ferroelectric storage device and circuit | Expired / Lapsed | 1951-12-14 | 1955-09-06 | 0 | Details |
| US2717372A | Ferroelectric storage device and circuit | Expired / Lapsed | 1951-11-01 | 1955-09-06 | 0 | Details |
| US2694160A | Expandable straight line trajectory radar and sonar indicat… | Expired / Lapsed | 1948-08-31 | 1954-11-09 | 0 | Details |
| US2681993A | Circuit element utilizing semiconductive materials | Expired / Lapsed | 1949-05-05 | 1954-06-22 | 0 | Details |
| US2676206A | Computation and display of correlation | Expired / Lapsed | 1951-12-06 | 1954-04-20 | 0 | Details |
| US2666356A | Servo system for nonintermittent film projectors | Expired / Lapsed | 1950-06-13 | 1954-01-19 | 0 | Details |
| US2657377A | Reproduction of signals from magnetic records | Expired / Lapsed | 1951-05-25 | 1953-10-27 | 0 | Details |
| US2655609A | Bistable circuits, including transistors | Expired / Lapsed | 1952-07-22 | 1953-10-13 | 0 | Details |
| US2652460A | Transistor amplifier circuits | Expired / Lapsed | 1950-09-12 | 1953-09-15 | 0 | Details |
| US2632062A | Semiconductor transducer | Expired / Lapsed | 1949-06-15 | 1953-03-17 | 0 | Details |
| US2617704A | Recording system | Expired / Lapsed | 1947-07-15 | 1952-11-11 | 0 | Details |
| US2614211A | Frequency controlled radio relaying system | Expired / Lapsed | 1950-05-13 | 1952-10-14 | 0 | Details |
| US2608621A | Magnetic record detector | Expired / Lapsed | 1949-10-08 | 1952-08-26 | 0 | Details |
| US2602211A | Rectifier and method of making it | Expired / Lapsed | 1945-12-29 | 1952-07-08 | 0 | Details |
| US2600500A | Semiconductor signal translating device with controlled car… | Expired / Lapsed | 1948-09-24 | 1952-06-17 | 0 | Details |
| US2599392A | Recording device | Expired / Lapsed | 1947-09-05 | 1952-06-03 | 0 | Details |
| US2592683A | Storage device utilizing semiconductor | Expired / Lapsed | 1950-12-30 | 1952-04-15 | 0 | Details |
| US2589130A | Permutation code group selector | Expired / Lapsed | 1949-06-24 | 1952-03-11 | 0 | Details |
| US2586080A | Semiconductive signal translating device | Expired / Lapsed | 1949-10-11 | 1952-02-19 | 0 | Details |
| US2582959A | Electron-tube controlled switching system | Expired / Lapsed | 1947-10-29 | 1952-01-22 | 0 | Details |
| US2577151A | Regulated rectifying apparatus | Expired / Lapsed | 1949-10-11 | 1951-12-04 | 0 | Details |
| US2572132A | Transcribing and summarizing system | Expired / Lapsed | 1949-04-27 | 1951-10-23 | 0 | Details |
| US2569347A | Circuit element utilizing semiconductive material | Expired / Lapsed | 1948-06-26 | 1951-09-25 | 0 | Details |
| US2564784A | Condenser | Expired / Lapsed | 1948-11-06 | 1951-08-21 | 0 | Details |
| US2564439A | Standard frequency system | Expired / Lapsed | 1946-10-30 | 1951-08-14 | 0 | Details |
| US2560594A | Semiconductor translator and method of making it | Expired / Lapsed | 1948-09-24 | 1951-07-17 | 0 | Details |
| US2555959A | Nonlinear reactance circuits utilizing high dielectric cons… | Expired / Lapsed | 1946-10-18 | 1951-06-05 | 0 | Details |
| US2552629A | Error-detecting and correcting system | Expired / Lapsed | 1950-01-11 | 1951-05-15 | 0 | Details |
| US2549422A | Decoder for multiple carrier pulse code modulation signals | Expired / Lapsed | 1949-01-06 | 1951-04-17 | 0 | Details |
| US2538615A | Decoder for reflected binary codes | Expired / Lapsed | 1948-02-10 | 1951-01-16 | 0 | Details |
| US2538636A | Digital computer | Expired / Lapsed | 1947-12-31 | 1951-01-16 | 0 | Details |
| US2535303A | Electronic switch | Expired / Lapsed | 1949-10-21 | 1950-12-26 | 0 | Details |
| US2530745A | Transistor microphone with conductive grains | Expired / Lapsed | 1948-12-10 | 1950-11-21 | 0 | Details |
| US2530824A | Secret carrier signaling method and system | Expired / Lapsed | 1946-08-20 | 1950-11-21 | 0 | Details |
| US2524034A | Three-electrode circuit element utilizing semiconductor mat… | Expired / Lapsed | 1948-02-26 | 1950-10-03 | 0 | Details |
| US2522521A | Thermal transistor microphone | Expired / Lapsed | 1949-01-14 | 1950-09-19 | 0 | Details |
| US2518022A | Translator | Expired / Lapsed | 1948-09-30 | 1950-08-08 | 0 | Details |
| US2511195A | Recording pen check mechanism | Expired / Lapsed | 1948-04-30 | 1950-06-13 | 0 | Details |
| US2509068A | Polarimetric method and means of determining the degree of … | Expired / Lapsed | 1948-02-20 | 1950-05-23 | 0 | Details |
| US2508511A | Resistor coated with ceramic composition | Expired / Lapsed | 1946-12-12 | 1950-05-23 | 2 | Details |
| US2505029A | Decoder for pulse code modulation | Expired / Lapsed | 1949-02-09 | 1950-04-25 | 0 | Details |
| US2494323A | Signal receiving apparatus | Expired / Lapsed | 1943-03-12 | 1950-01-10 | 0 | Details |
| US2493183A | Artillery director | Expired / Lapsed | 1942-05-21 | 1950-01-03 | 0 | Details |
| US2484226A | Indicating circuit | Expired / Lapsed | 1947-10-17 | 1949-10-11 | 0 | Details |
| US2484618A | Wave receiving system | Expired / Lapsed | 1944-08-26 | 1949-10-11 | 0 | Details |
| US2460401A | Directive microwave radio antenna | Expired / Lapsed | 1943-04-01 | 1949-02-01 | 0 | Details |
| US2455520A | Temperature controlled test system | Expired / Lapsed | 1944-03-24 | 1948-12-07 | 0 | Details |
| US2453461A | Code modulation communication system | Expired / Lapsed | 1946-06-19 | 1948-11-09 | 0 | Details |
| US2450516A | Telemetric data transmission system | Expired / Lapsed | 1944-01-11 | 1948-10-05 | 0 | Details |
| US2444349A | Cyrstal oscillator circuits | Expired / Lapsed | 1945-10-31 | 1948-06-29 | 0 | Details |
| US2442702A | Selective signaling system | Expired / Lapsed | 1945-09-20 | 1948-06-01 | 0 | Details |
| US2438893A | Translating device | Expired / Lapsed | 1943-12-29 | 1948-04-06 | 0 | Details |
| US2433382A | Recorder system with electromagnetically attracted electric… | Expired / Lapsed | 1944-09-11 | 1947-12-30 | 0 | Details |
| US2433002A | Pulse-type position indicator | Expired / Lapsed | 1944-09-29 | 1947-12-23 | 0 | Details |
| US2432116A | Crystal detector mounting | Expired / Lapsed | 1943-04-19 | 1947-12-09 | 0 | Details |
| US2431696A | Relay desing calculator | Expired / Lapsed | 1944-08-23 | 1947-12-02 | 0 | Details |
| US2430447A | Printing telegraph automatic switching system | Expired / Lapsed | 1942-06-27 | 1947-11-11 | 0 | Details |
| US2427348A | Piezoelectric vibrator | Expired / Lapsed | 1941-08-19 | 1947-09-16 | 0 | Details |
| US2425003A | Analysis and representation of complex waves | Expired / Lapsed | 1944-12-23 | 1947-08-05 | 0 | Details |
| US2424246A | Frequency-modulated crystal oscillator | Expired / Lapsed | 1943-09-16 | 1947-07-22 | 0 | Details |
| US2422698A | Time measuring system | Expired / Lapsed | 1942-11-05 | 1947-06-24 | 0 | Details |
| US2421919A | Telephone routing system | Expired / Lapsed | 1944-04-29 | 1947-06-10 | 0 | Details |
| US2421747A | Object locating system | Expired / Lapsed | 1943-07-14 | 1947-06-10 | 0 | Details |
| US2414479A | Impulse generator | Expired / Lapsed | 1942-11-05 | 1947-01-21 | 0 | Details |
| US2412642A | Electronic telegraph transmitter distributor | Expired / Lapsed | 1943-08-25 | 1946-12-17 | 0 | Details |
| US2412210A | Cathode-ray sweep circuit | Expired / Lapsed | 1942-03-21 | 1946-12-10 | 0 | Details |
| US2406353A | Secret signaling | Expired / Lapsed | 1943-07-17 | 1946-08-27 | 0 | Details |
| US2405242A | Microwave radio transmission | Expired / Lapsed | 1941-11-28 | 1946-08-06 | 0 | Details |
| US2403984A | Representation of complex waves | Expired / Lapsed | 1945-04-03 | 1946-07-16 | 0 | Details |
| US2402662A | Light-sensitive electric device | Expired / Lapsed | 1941-05-27 | 1946-06-25 | 0 | Details |
| US2395259A | Method of making dry rectifiers | Expired / Lapsed | 1942-10-24 | 1946-02-19 | 0 | Details |
| US2381920A | Telemetric device | Expired / Lapsed | 1944-02-17 | 1945-08-14 | 0 | Details |
| US2381871A | Communication system | Expired / Lapsed | 1941-03-15 | 1945-08-14 | 0 | Details |
| US2366733A | Communication system | Expired / Lapsed | 1941-08-28 | 1945-01-09 | 0 | Details |
| US2347733A | Switching device | Expired / Lapsed | 1941-06-06 | 1944-05-02 | 0 | Details |
| US2347098A | Electrical wave modulation | Expired / Lapsed | 1942-01-09 | 1944-04-18 | 0 | Details |
| US2344792A | Motor control mechanism for printing telegraph apparatus | Expired / Lapsed | 1941-11-27 | 1944-03-21 | 0 | Details |
| US2339406A | Electrical transmission system | Expired / Lapsed | 1941-05-31 | 1944-01-18 | 0 | Details |
| US2338636A | Automatic billing system | Expired / Lapsed | 1937-12-08 | 1944-01-04 | 0 | Details |
| US2336373A | Teletypewriter switching system | Expired / Lapsed | 1940-06-15 | 1943-12-07 | 0 | Details |
| US2332912A | Telephone system | Expired / Lapsed | 1942-05-01 | 1943-10-26 | 0 | Details |
| US2319339A | Signaling system | Expired / Lapsed | 1940-05-22 | 1943-05-18 | 0 | Details |
| US2303377A | Communication system with voiceoperated switching mechanisms | Expired / Lapsed | 1941-07-23 | 1942-12-01 | 0 | Details |
| US2300505A | Selective system | Expired / Lapsed | 1940-10-31 | 1942-11-03 | 0 | Details |
| US2294464A | Impulse transmitter | Expired / Lapsed | 1938-04-09 | 1942-09-01 | 0 | Details |
| US2292388A | Rochelle salt piezoelectric crystal apparatus | Expired / Lapsed | 1941-05-23 | 1942-08-11 | 0 | Details |
| US2291224A | Selecting system | Expired / Lapsed | 1941-02-08 | 1942-07-28 | 0 | Details |
| US2285166A | Tension gauge | Expired / Lapsed | 1940-01-11 | 1942-06-02 | 0 | Details |
| US2283935A | Transmission, radiation, and reception of electromagnetic w… | Expired / Lapsed | 1938-04-29 | 1942-05-26 | 0 | Details |
| US2279319A | Electric wave circuit | Expired / Lapsed | 1941-05-28 | 1942-04-14 | 0 | Details |
| US2276665A | Pulse regenerator | Expired / Lapsed | 1940-10-25 | 1942-03-17 | 0 | Details |
| US2275977A | Means for calibrating scales | Expired / Lapsed | 1938-09-28 | 1942-03-10 | 0 | Details |
| US2267827A | Electric signaling system | Expired / Lapsed | 1939-07-26 | 1941-12-30 | 0 | Details |
| US2266416A | Control apparatus | Expired / Lapsed | 1939-01-14 | 1941-12-16 | 0 | Details |
| US2254601A | Automatic measuring of cross talk | Expired / Lapsed | 1940-04-03 | 1941-09-02 | 0 | Details |
| US2253577A | Resistance device | Expired / Lapsed | 1939-04-07 | 1941-08-26 | 0 | Details |
| US2250100A | Signaling system | Expired / Lapsed | 1939-11-14 | 1941-07-22 | 0 | Details |
| US2250156A | Electrical connection | Expired / Lapsed | 1939-06-02 | 1941-07-22 | 0 | Details |
| US2245660A | Radio system | Expired / Lapsed | 1938-10-12 | 1941-06-17 | 0 | Details |
| US2244500A | Telephone system | Expired / Lapsed | 1938-09-30 | 1941-06-03 | 0 | Details |
| US2236246A | Telephone system | Expired / Lapsed | 1939-09-15 | 1941-03-25 | 0 | Details |
| US2228266A | Signal translating apparatus | Expired / Lapsed | 1939-07-01 | 1941-01-14 | 0 | Details |
| US2223224A | Radio speed and drift indicator | Expired / Lapsed | 1939-06-24 | 1940-11-26 | 0 | Details |
| US2222688A | Vibratory frequency controlling device | Expired / Lapsed | 1939-04-19 | 1940-11-26 | 0 | Details |
| US2222425A | Magnetic structure | Expired / Lapsed | 1938-08-20 | 1940-11-19 | 0 | Details |
| US2220883A | Circuit controller | Expired / Lapsed | 1939-07-08 | 1940-11-12 | 0 | Details |
| US2219888A | Extruding apparatus | Expired / Lapsed | 1938-09-15 | 1940-10-29 | 0 | Details |
| US2202060A | Alarm system | Expired / Lapsed | 1936-12-12 | 1940-05-28 | 0 | Details |
| US2199083A | Transmission of guided waves | Expired / Lapsed | 1937-09-04 | 1940-04-30 | 0 | Details |
| US2173858A | Radio system | Expired / Lapsed | 1937-06-23 | 1939-09-26 | 0 | Details |
| US2168047A | Electro-optical system | Expired / Lapsed | 1936-12-24 | 1939-08-01 | 0 | Details |
| US2129669A | Guided wave transmission | Expired / Lapsed | 1937-05-19 | 1938-09-13 | 0 | Details |
| US2129711A | Guided transmission of ultra high frequency waves | Expired / Lapsed | 1933-03-16 | 1938-09-13 | 0 | Details |
| US2128412A | Cable plug | Expired / Lapsed | 1936-11-28 | 1938-08-30 | 0 | Details |
| US2116593A | Cutting or milling machine | Expired / Lapsed | 1934-04-13 | 1938-05-10 | 0 | Details |
| US2115917A | Picture transmitting system | Expired / Lapsed | 1925-03-12 | 1938-05-03 | 0 | Details |
| US2113220A | Rectifier system | Expired / Lapsed | 1936-06-01 | 1938-04-05 | 0 | Details |
| US2112951A | Telephone system | Expired / Lapsed | 1934-04-28 | 1938-04-05 | 0 | Details |
| US2099876A | Strand handling apparatus | Expired / Lapsed | 1934-06-09 | 1937-11-23 | 0 | Details |
| US2097501A | Electrical cable and a method of making the same | Expired / Lapsed | 1933-07-12 | 1937-11-02 | 0 | Details |
| US2066332A | Carrier wave transmission system | Expired / Lapsed | 1934-12-14 | 1937-01-05 | 0 | Details |
| US2044470A | Impulse sender | Expired / Lapsed | 1933-04-12 | 1936-06-16 | 0 | Details |
| US1992268A | Acoustic device | Expired / Lapsed | 1933-04-11 | 1935-02-26 | 0 | Details |
| US1992271A | Automatic stock quotation system | Expired / Lapsed | 1931-09-17 | 1935-02-26 | 0 | Details |
| US1988609A | Synchronizing system | Expired / Lapsed | 1931-07-21 | 1935-01-22 | 0 | Details |
| US1981999A | Optical telephone system | Expired / Lapsed | 1932-08-20 | 1934-11-27 | 0 | Details |
| US1972985A | Electric switching device | Expired / Lapsed | 1930-09-23 | 1934-09-11 | 0 | Details |
| US1968420A | Telephone system | Expired / Lapsed | 1933-02-16 | 1934-07-31 | 0 | Details |
| US1840112A | Artificial larynx | Expired / Lapsed | 1927-12-17 | 1932-01-05 | 0 | Details |
| US1772167A | Signaling system | Expired / Lapsed | 1926-12-31 | 1930-08-05 | 0 | Details |
| US1771148A | Central energy wave signaling system | Expired / Lapsed | 1923-06-29 | 1930-07-22 | 0 | Details |
| US1667792A | Radio signaling system | Expired / Lapsed | 1923-01-11 | 1928-05-01 | 0 | Details |
| US1630451A | Method of producing coated cores | Expired / Lapsed | 1925-02-14 | 1927-05-31 | 0 | Details |
| US1610910A | Composite article and method of forming it | Expired / Lapsed | 1924-10-16 | 1926-12-14 | 0 | Details |
| US1593993A | Selective system | Expired / Lapsed | 1921-11-10 | 1926-07-27 | 0 | Details |
| US1565596A | Signal system | Expired / Lapsed | 1923-11-15 | 1925-12-15 | 0 | Details |
| US1465352A | Electrical testing system | Expired / Lapsed | 1920-09-27 | 1923-08-21 | 0 | Details |
| US1394642A | Electric signaling system | Expired / Lapsed | 1919-11-12 | 1921-10-25 | 0 | Details |
| US1381451A | Switching system | Expired / Lapsed | 1919-06-24 | 1921-06-14 | 0 | Details |
| US1378960A | Method of and apparatus for detecting under-water vibrations | Expired / Lapsed | 1919-06-24 | 1921-05-24 | 0 | Details |
| US1378950A | Recording-key | Expired / Lapsed | 1918-12-04 | 1921-05-24 | 0 | Details |