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4586186 Maintenance response signalling arrangement for a digital transmission system  
A maintenance response signalling arrangement for a digital transmission system transmits response signals from a repeater to an end terminal. From the repeater, response information is modulated...
4570257 Communication system with slot time error detection  
A data communication system allocates use of a common data communication medium shared by a plurality of stations. During each transmission cycle, the communication medium carries data packets of...
4562571 Speech processing device for radioelectric equipment adapted for speech transmission and reception  
The device is of the type comprising a circuit for compressing the dynamic of the speech signal before transmission of the signal at constant level and an expander for re-establishing at reception...
4528662 Multiplex control system having enhanced integrity  
A serial data communications system, particularly for use in an automotive environment is disclosed in which bidirectional serial data communication is effected between a central control station...
4506360 Multi-station token pass communication system and method  
A data communications system is disclosed which uses a passive communications medium such as coaxial cable for communication between multiple stations connected to the bus. A token concept is...
4455647 Apparatus for establishing multi-address connections  
A digital data telecommunications system comprises a central switching system and a plurality of line terminators each connecting the switching system to a pair of incoming and outgoing lines and...
4399531 Distributed digital data communications network  
A distributed digital data communication network having widely dispursed nodes provides for effective transmission of messages between each node through the use of flood routing. A response message...
4385380 Digital concentrator switch  
In a fully digital telephone switching system, a digital switch may serve a number of PCM sub systems each having separate forward and reverse highways and each serving a number of subscribers'...
4381427 Subscriber loop system for voice and data  
A subscriber loop system in association with a TDM telephone system provides voice and data communication with a remote telephone station set and an associated data port. The subscriber loop system...
4370561 Vehicle multiplex system  
A vehicle multiplex system includes a power conductor for conveying electrical power to power-operated units on the vehicle, and a single signal conductor for controlling the connections of power...
4287592 Method and apparatus for interfacing stations in a multiloop communications system  
A multiloop communications system and a method of routing data between stations is disclosed. The communications system has a plurality of interconnected communications loops, each of the loops...
4273955 System for in-service quantitative performance analysis of data communications system  
A data communication system is provided comprising, at a plurality of locations, data terminal equipment. Communication equipment adapted to transmit and/or receive data from location to location...
4245342 One-for-n modem control apparatus  
Communications apparatus includes one-for-n modem redundancy for a plurality of typically contiguously disposed modem modules. The modem modules comprise n active units each illustratively...
4229816 Timing signal generation and distribution system for TDM telecommunications systems  
Synchronous operation of any number of digital switching units of a TDM system is maintained by interconnecting the switching units to a timing signal highway which distributes timing signals...
4213015 Failure alarm for a transmission line communications system  
A power failure alarm circuit for a transmission line communications system such as a telephone system having means for transmitting and receiving carrier signals connected to a trunk line at an...
4144406 Time-multiplex modular switching network for automatic exchange  
The time-switching network according to the invention has an inlet stage, an outlet stage, and a selection switching stage, respectively comprising M, M, and N groups. It includes line equipments;...
4127816 Carrier detect and automatic loopback circuit  
A master station communicates with remote stations by respective transmit-receive pairs. Quadra-phase modulation is utilized, involving a carrier having two characteristic frequencies not present...
4096354 Apparatus for distinguishing between failures in a digital transmission network  
At a channel bank, such as a D-type channel bank used in the Bell System, a steady visual alarm is exhibited if the source of a detected failure is at a location either within the channel bank or...
4059731 Signaling storage in digital channel banks  
In a digital channel bank, the binary signaling states (on-hook, off-hook) are updated periodically for each channel. Some number (n ≥ 2) of the most recent of these samples are stored at the...
3962646 Squelch circuit for a digital system  
A digital system for receiving digital messages transmitted in a polybinary code having a squelch circuit for inhibiting operation of the system during improper operation, said squelch system...
3940566 Arrangement for preventing interruptions in a time division multiplex transmission link for transfer of data  
The present invention relates to an arrangement in a time division multiplex link having at least two pairs of multiplexors and demultiplexors interconnected by separate transmission lines, i.e.,...
3920921 Line equipment for scan and control system for synchronized PCM digital switching exchange  
Among the line equipment serving a synchronized PCM TDM digital switching exchange, there is provided a supervisory scan and control system for interfacing the operation of incoming and outgoing...
3839707 FAULT-ALARM AND CONTROL FOR A MICROWAVE COMMUNICATION NETWORK  
A maintenance system and method is provided to alarm faults detected in a switched-data microwave communications network, and to initiate control messages for corrective action. Located at the...
3829777 CONTROL SYSTEM FOR DIVERSITY TRANSMISSION IN A TERRESTRIAL STATION OF SATELLITE COMMUNICATION  
A control system for diversity transmission from a terrestrial station which performs time-division multiple access to a satellite communication repeater through a selected one of a plurality of...
3809818 MEANS AND METHOD FOR TELEPHONE LINE DISCONNECTION IN FREQUENCY DIVISION MULTIPLEXING  
Transmission failure in frequency division multiplexing connected to telephone systems results in the generation of a disconnect tones, one for each carrier, which are simultaneously superimposed...
3725593 PCM TELECOMMUNICATION SYSTEM WITH STANDBY CLOCK  
At a main terminal connected to a remote terminal by way of a PCM signal path, a master clock controls the multiplexing of incoming messages from local lines for transmission over an outgoing line...
3622707 MULTIPLE CHANNEL SUBSCRIBER LOOP  
A time division multiplex system for use with subscriber stations utilizes a pilot tone to control switches which connect subscribers to the common line during designated portions of each cycle....
3614327 DATA MULTIPLEXER USING TREE SWITCHING CONFIGURATION  
A data multiplexer is disclosed in which FETs are arranged in a tree switching configuration of n columns and are driven by n drivers to control the multiplexing of data from 2 n sources. Each...
3564145 SERIAL LOOP DATA TRANSMISSION SYSTEM FAULT LOCATOR  
Terminals in a serial loop data transmission system automatically monitor input data to detect no data and mutilated data conditions. When either condition is detected, signals including the unique...
3227809 Time division multiplex electrical signalling systems  
3157744 System for coordinating a plurality of synchronized time division multiplex systems  
3138670 Automatic test equipment for multiterminal communication systems  
3099716 Diversity communication system  
2986610 Alarm and test equipment for carrier systems  
2927968 Line switching systems