Abstract: A video conversational data communication network (30) in which subscribers (34, 35) may conduct conversational video textual data communications with one or more keystations (70, 602, 98) the network (30). Each keystation (70, 602, 98) is associated with a keystation terminal controller interface (68, 96, 600) which is in turn connected to a message switching node (32) for routing calls throughout the network (30). The keystation controller interface (68, 96, 600) locally stores (304, 306) video conversational textual data for its associated keystations (70, 82, 84, 98, 100, 602) and enables two different designated keystations to conduct two different video conversations with a common keystation in a split screen display (76). The split screen display (76) may also be used to display retrievable data from a data base (50, 52) for simultaneous display (76) along with a video conversation.

Abstract: An audio-visual line test termination device for providing a characteristic signature to the telephone central office and a visual and an audible signal to the customer when a continuity test is made on a subscriber line having a pair of electrically conductive paths includes a miniature audio indicator, a light source and a minimum of associated electrical components to indicate to the central office test operator and the customer that the telephone subscriber line is in operating order. The instant invention may be utilized together with a housing that may be permanently installed across the subscriber line.

Abstract: A digital telecommunication system has a plurality of 64 kbit/s channels subdivided into respective 56 kbit/s primary channels and 8 kbit/s auxiliary channels. Continuously from subscriber-to-subscriber, the 56 kbit/s primary channels serve respectively alternately for the transmission of pulse code modulated or delta modulated speech signals and/or rapid fixed image transmission or rapid data transmission, whereas the 8 kbit/s auxiliary channels are only available for the transmission or exchange-oriented signaling characters, slow fixed image transmission, slow data transmission from subscriber-to-subscriber, as well as for transmission of subscriber-to-subscriber control information and/or remote control and similar special service information.

Abstract: A telephony network with a digital central office and a one or more remotely located digital satellite units. Each digital satellite unit connects to a number of remote subscriber lines and monitors these lines to establish communications through interconnecting spans and a digital satellite interface at the digital central office. The digital satellite interface includes a programmed controller that communicates with the remote digital satellite units connected to it, with call processing equipment in the digital central office and with maintenance processing equipment in the digital central office. Communications with the maintenance processor are in the form of messages having a header byte and a byte indicating the length of the message. During network initialization and various recovery operations, the programs and/or the data base can be transferred from the maintenance processor to each digital satellite interface through the use of these messages.

Abstract: Apparatus for transmission of information in digital form comprising apparatus for providing a plurality of signals coded into a multiplicity of digital code elements in accordance with a first modulation technique; and apparatus for providing a plurality of coded addresses for transmission, each of the coded addresses representing a digital code in accordance with a second modulation technique corresponding to a combination of code elements of individual ones of the plurality of signals.

Abstract: A digital conference circuit for a digital telephone switching network is provided, connected between a receive TDM (time division multiplex) bus carrying PCM (pulse code modulation) words to the conference circuit and a transmit TDM bus carrying PCM words from the conference circuit. A memory (storage) device stores the PCM words most recently received on the receive TDM bus and decision circuitry determines, for each conferee, which two PCM words, excluding the PCM word originating from that conferee, should be read from the memory device. The two PCM words so read are attenuated in a predetermined fashion, summed, and the resultant PCM sum applied to the transmit TDM bus during an appropriate timeslot. The decision circuit makes its decision based upon the largest average magnitude of each conferee's PCM words, received at the conference circuit, during the previous frames.

Abstract: In a digital transmission system, a loop-timing technique is provided for a channel bank which demultiplexes a high speed data stream into a plurality of lower rate channels, and which multiplexes a plurality of lower rate channels to a high speed data stream. Loop-timing is provided without elastic buffers by deriving stuff requests from stuff bits in the received high speed data stream, extracting a high speed clock signal from the received data stream, and applying the stuff requests and the high speed clock signal directly to the high speed multiplexer for providing stuff bits in the transmitted high speed data stream and for clocking the transmitted high speed data stream.

Abstract: A matrixed, optical keyboard comprising structure 10 defining an array of touch areas 14 arranged in rows 16 and columns 17, and paired light sources and light sensors 20, 22 disposed at opposite ends of each row and each column and positioned to define a path of light. Light refocussing elements 24 are disposed contiguously about and define the touch areas and extend into the light path thereby refocussing the light beam prior to traversing each touch area and prior to impinging on the associated light sensor. In one embodiment, the keyboard and light refocussing elements are integrally molded and form a unitary structure. In another embodiment, the keyboard is formed with structure for maintaining an indicia card 44 behind and in alignment with the touch areas so that indicia area 44a are visible through the touch areas 14'.

Abstract: A loop network is disclosed in which the ports have access to time slots on each of two buses. The buses carry the time slots in opposite directions. Ports are addressed by marking a bit of a time slot word on one bus and a bit of a time slot word on the other bus so that the two marked bits will arrive within a predetermined number of bit intervals of each other at the addressed port. Time slots are seized by an upstream port writing a predetermined pattern into an arriving idle time slot and by the downstream port recognizing the arrival of that predetermined pattern. A time slot may be reused during the remainder of its passage around the loop after it is rendered idle by the downstream port of a connection.

Abstract: A switching unit for the selective transfer of bytes concurrently arriving in successive time slots over eight incoming signal paths to as many outgoing signal paths with intervening temporal and/or spatial transposition comprises a byte memory loaded by way of a series/parallel converter and read out by way of a parallel/series converter; two 8.times.8 storage matrices may alternately serve as the two converters. A routing memory, connected via a logic network to a command unit such as a microprocessor, controls the transfer and may also block the readout from the byte memory under certain conditions, specifically during an initiation procedure or where the switching unit is one of several such units forming part of a larger switching or concentration structure. In response to particular instructions from the command unit, a single byte from an incoming path may be transferred to one or all of the outgoing paths.

Abstract: A telemetry system including a number of series connected modules having clock inputs and outputs and reset inputs and outputs, each module coupling an associated digital data sources to a master station via a common data bus. Circuitry is provided in each module whereby a self perpetuating reset signal from the master station and successive clock pulses from the master station actuate and deactuate the modules in sequence to multiplex data from all of the digital data sources onto the common data bus.

Abstract: In an exemplary embodiment, subscriber lines are formed by means of light waveguides and transmit pulse-modulated TV signals in time-division multiplex. These pulse-modulated signals are converted into PAM signals at the subscriber side, from whose frequency spectrum formed by a sequence of frequency bands, respectively one frequency band arrives via a subscriber-allocated distributor line operated in frequency-division multiplex to a video receiver now being operated at the subscriber location.

Abstract: An apparatus for testing a data multiplex transmission system by providing simulated source and sink of data for the multiplex transmission system that is compatible with the multiplex system and complies with the protocol of the Input/Output modules of the multiplex system. A programmable read only memory is programmable by means of toggle and thumbwheel switches to selectively and variably control the protocol, the length, the rate, the destination and the content of the data message. A status display is connected to the programmable read only memory to indicate the current point of progression of its programmable sequence. An error detector is connected to the programmable read only memory for determining whether the memory has stalled at a point of progression and an error display is also connected to the programmable read only memory to indicate and identify the error when this stall condition has occurred.

Abstract: A detector for detecting the passage of heavy objects on a roadway, wherein the detector is an elongate strip in the form of nested channel-section members, said members comprising, from the outside towards the insidea first channel section bar (1) made of a strong material;a second channel section bar (2) made of a shock-absorbing material embedded in the channel of said first bar;a third channel section bar (3) made of a strong material embedded in the channel of said second bar; anda sensor (4) embedded in the channel of said third bar.

Abstract: A time slot interchanger is disclosed for selecting and buffering digital signals between buses. The arrangement is particularly useful in forming conferences in a distributed digital time division system. In one embodiment, a clock is used to generate time signals corresponding to time slots of the first bus. These signals are sequentially provided to an associative memory and when a match occurs between the provided signal and a priorly stored time slot identity, an enable signal is provided. The enable signal has a time identity with a first bus time slot and a physical identity with a particular second bus time slot. The enable signal is used to gate into a second memory the time slot signal associated with the time identity at the storage location in the second memory corresponding with the particular time slot of the second bus associated with the enable signal. The signal samples are then sequentially removed from the second memory.

Abstract: An apparatus and method for obtaining an electrical signal indicative of the degree of extension of a fluid cylinder, the signal being transmitted to a remote location for use in providing a remote readout of the cylinder position. The displacement of the piston is translated into a rotational movement of a threaded rod coupled to the piston. The rod is, in turn, coupled to a potentiometer or other device that provides an electrical signal indicative of the cylinder extension.

Abstract: To provide a rugged vibration and shock-insensitive position transducer, a coil is wound on a lamella-like carrier which has a body element of electrically insulating material on which, at least on one surface, a foil of magnetically highly permeable material is positioned; these lamella-foil combinations can be stacked, or a unitary body which foils on both sides can be provided. A short-circuit ring, movable along the core, changes the inductance of the coil wound thereon, the value of which can be determined by energizing the coil with alternating current.

Abstract: The signal term to be transmitted to a railroad traction vehicle is formed in a signaling system in that each element, from a destination element back to a start element has a respective top speed assigned thereto as an identification. The identification is transmitted element-by-element back to the start element and is devalued during relaying thereof when the identification is greater than that prescribed for a travel path element having a lower assigned top speed so that the identification received at the start element indicates the top speed admissible for the route. The admissible top speed is then converted into a corresponding signal term.

Abstract: 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 includes a voice path and a data path. Supervisory and signalling circuits in the telephone set are used for generating and registering call control signals pertaining to both voice and data calls. The call control signals are labelled and multiplexed with data signals by local and remote line interface circuits for transmission therebetween. A codec in the voice path is caused to couple call progress signals (i.e. dial tone, ring back) to the telephone set during a data call progress, for audible signalling to a user.

Abstract: A system for detecting and measuring corrosive reaction of metals in an environment. The system includes: a remotely placeable sensor head containing a galvanic couple made of metals identical to those involved in the corrosion problem, with the couple coiled in the shape of a sprial; and, operatively associated electronic circuitry to amplify, integrate, and store in a non-volatile memory, e.g., a bubble type memory, for future recall the amount of galvanic current that is flowing and that has flowed when corrosion is, or has been, occurring.