Abstract: Digital signal cross connect communication systems include a plurality of tracer circuits within a particular shelf, a plurality of shelves within a particular rack, a plurality of racks within a particular row, and, generally, a plurality of rows within the office in which the circuitry of the digital signal cross connect communication system is located. In order to facilitate a technician in determining the specific location of an engaged tracer circuit, row indicator lamps may be provided to indicate the particular row the engaged tracer circuit is located in. Also, rack lamp indicators located above each rack and shelf lamp indicators located within each shelf may also be provided to indicate the particular rack and shelf an engaged tracer circuit is located.

Abstract: A data transmission control processing system comprising the steps of easily realizing the reading, writing of the memories of the other terminals coupled with the above described transmission passages in a system where a plurality of terminals provided with a transmitting, receiving control processing portion for transmitting receiving the control signals are coupled by transmitting passages so as to effect the mutual communication, realizing the writing onto the memories by a system similar to the reading of the memories when the above described system is a system by the D2B, being capable of easily coping with respect to the expansion of the reading.writing control operation of the memories, simplifying the realization of the reading.writing control sequence which is adapted to reduce the amount of the telegraphic messages to be exchanged in the reading.writing operation of the memories on the other terminal.

Abstract: An arrangement for data conferencing either multiple computers (FIG. 1), or multiple terminals with a computer (FIG. 4), includes software (21;511) for communicating keystrokes from conference participants to an application program (22;550) that is the object of the conference, and for communicating display signals from the application program to the participants. In one embodiment (FIG. 1), a first program (23) executing on a first computer (PC 2) transmits first computer-generated keystrokes to a second computer (PC 1), and displays on the first computer images received from the second computer, while a second program (21) co-resident with the application program (22) on the second computer enters received first computer keystrokes into the second computer, and sends second computer-generated images for display to the first computer. In a second embodiment (FIG. 4), a program (511) executing on a UNIX.RTM.

Abstract: A modem system includes an RS232C interface; a modulator/demodulator; an input-output device having a parallel interface connected with a data terminal unit having no communication function or having a parallel specification; a parallel-to-serial converter for performing the mutual conversion between parallel data and serial data; a memory for temporally storing the transmitted or recieved data; and a controller for controlling the transmission and reception of data. The modem system can perform the convertion between RS232C specification data and centronix specification data such that a parallel specification printer or plotter having no communication function can be used as an output device for data transmitted to the modem system through the telephone network.

Abstract: Apparatus and method are disclosed for determining the location of a network component coupled to a local area network segment. A remote segment monitor unit is coupled to either end of a cable segment of a local area network system. The remote segment monitor unit, for each transaction on the cable segment, determines a value related to the transaction signal strength and determines the identity of the network node from which the transaction originated. By providing a record of the transaction signal strength associated with each network node (component) in both remote segment monitors, the location of network nodes can be ascertained.

Abstract: Apparatus and method are disclosed for providing a calibrated measurement of signals applied to a local area network cable segment. A remote segment monitor unit has the signal sampling circuit coupled to a signal generating unit. The signal generating unit is controlled by a network system member (node) and applies a series of known signal levels to the signal sampling circuit of the remote segment monitor unit. The known signal levels from the signal generating unit and the signal levels measured by the remote segment monitor as a result of the known signal levels are compared and an appropriate scale factor entered in the processing circuit of the remote segment monitor. Using the calibrated remote segment monitor, the location of network nodes can be identified from the signal levels measured by the remote segment monitor.

Abstract: A method provides for the current address tables present in a respective subscriber equipment monitoring a ring-shaped network to be distributed to all subscriber equipment of the n ring-shaped networks connected therto. After the existence of the current address tables, distribution information are formed in the subscriber equipment monitoring the ring-shaped networks and are transmitted to the further subscriber equipment of the respective ring-shaped networks. When a subscriber equipment has access to a further ring-shaped network, this, in turn, forms a further distribution information and transmits the same to its appertaining ring-shaped network.

Abstract: A device for transmitting data between a transmitter provided with standard software adapted to a serial interface and a standard receiver provided with a serial interface is presented. The device includes a serial interface simulator which replaces the serial interface of the transmitter, a memory which stores data received by the serial interface simulator, and an interface which transmits to the receiver the data stored in the memory. The serial interface simulator includes a data transmission register, a data reception register, a first buffer register, a second buffer register, a bus, a simulation control register and a simulation state register.The standard software places data in the data transmission register and receives data from the data reception register. Data placed in the data transmission register is not immediately serially transmitted to the receiver, but is transferred to the first buffer register from where it is transferred to the memory.

Abstract: In a communication system having an automatic transmission/reception function to perform data communications through telephone lines associated with teletex systems, facsimile systems and the like, re-transmission operations are performed when an addressee called for communications is busy (calling) or when communications is interrupted after an addressee has responded. In the re-transmission operation, a response from an addressee is detected and decided as to whether the response is automatically originated from a communication unit or originated by a person. When the latter response is detected, a wrong telephoning is decided and restrictions are placed on the re-transmission operation to thereby minimize trouble given to the addressee.

Abstract: A circuit for the transmission of data signals between subscriber terminals operating with different data transmission procedures is described. Data signals are transmitted between a subscriber terminal operating with a first transmission procedure and a subscriber terminal operating with a second transmission procedure, attainable only through manually switched connections. A manual switchboard having at least one job memory unit and a control unit is provided. Jobs for connections to be manually switched, respectively containing at least a job number, as well as selection data, serving for the establishment of connections and data signals to be transmitted, are written into the job memory unit. These jobs are output in the sequence in which they were input, such that the control unit maintains, for each job, only the selection data required for the setting-up of a connection and the associated data signals for a conversion and related forwarding.

Abstract: In a measuring system, a measuring signal is transmitted on a two-wire line by varying the DC supply current which is transmitted on the same two-wire line. In addition, binary-coded information signals are transmitted via the same two-wire line, each bit of the one binary value being represented by a group of a predetermined number of consecutive periods of a periodic signal, and each bit of the other binary value being represented by the absence of the same number of consecutive periods of the periodic signal. On reception, received periods of the periodic signals are counted in a first counting direction and missing periods are counted in the opposite counting direction between two limit counts. Reception of the one binary value is indicated when the first limit count is reached, and reception of the other binary value is indicated when the second limit count is reached.

Abstract: A steno translator system for translating stenographic keystrokes to language format according to a predefined keystroking methodology includes a steno writer to generate a sequence of stroke symbols each having associated therewith language parts consisting of suffixes, prefixes, word parts, punctuation and language symbols. A processor is coupled for receiving the stroke symbols and includes memory for storing a list of stroke entries, each represented by at least one stroke symbol, and an associated language part defining the translation for that stroke entry. The stroke entries are arranged in the memory in accordance with the predefined stroke entry order. The processor also includes a translator for segmenting the sequence of stroke symbols into a plurality of consecutive subsequences where each of the subsequences includes at least one stroke symbol and has a corresponding matching stroke entry in the memory.

Abstract: A direction sensitive coupling unit, and method of operation, is disclosed for use in a communication medium to indicate the presence and source direction of transmissions. A directional coupler is provided for receiving information signals from first and second directions along the medium and for providing an attenuated information signal as its output wherein the attenuation to information signals received from the first direction is greater than the attenuation to signals received from the second direction. A voltage sensitive indicating circuit is coupled to the medium and is adapted to respond to the coupler output for providing a digital indication of the presence and source direction of transmissions on the medium.

Abstract: The invention concerns device for transmitting and receiving a message by means of the tactile sensation. By means of keys (2), a code corresponding to one character is formed at a time, which code is converted by the device into an electric signal. The electric signals can be stored in a tape recorder (15), transmitted via a modem (6) into the telecommunication network, or be converted by means of a typewriter (4) into inkprint. Correspondingly, electric signals coming from these peripheral devices can be coded as a mark on feeling keys (3). The device is above all intended as means of conversation and study for deaf-blind persons.

Abstract: A data transmission facility comprises a central station and a plurality of substations connected thereto via a data bus, the substations outputting a control signal dependent on the transmission or reception condition thereof. A plurality of substations are therefore capable of being connected to a serial point-to-point interface of the central station by way of a coupling device which is reversible with respect to the direction of transmission by optional activation or deactivation of level converters on the basis of control signals transmitted by the central station or by the substations. The data transmission facility is particularly suited for the transmission of operating state signals from intermediate locations of a communications transmission facility to a central evaluation facility.

Abstract: A system for transmitting data signals between control devices connected to each other by a transmission loop operated directionally dependent has a number of such control devices connected to the loop, with each control device including a signal compiler which compiles data signals to be transmitted in the form of a data signal block which includes at least one receiver address identifying another control device which is intended to receive the transmitted signal block. The signal compiler is followed by a transmit buffer which includes an intermediate storage. A prepared data signal block is accepted in the intermediate storage. A buffer control is connected to the intermediate storage. A transmit authorization signal is transmitted via the loop from control device to control device. Upon receipt of the transmit authoriztion signal by the relevant control device, the buffer control therein enables a word-by-word read-out of the data signal block stored in the intermediate storage.

Abstract: A data transmission system has a number of control devices connected via a transmission loop. Each control device includes signal processing circuitry which compiles data signals to be transmitted in the form of a data signal block. The signal processing circuitry is followed by a transmit buffer, which includes a write/read memory. A prepared data signal block can be accepted into this memory. A counter is connected to the memory which continuously addresses the memory for accepting a data signal block, and for emission thereof to the loop upon the appearance of a transmit authorization signal. The write/read memory is followed by a register. In addition to memory locations for accepting a data signal word, this register additionally includes memory locations for auxiliary information to be attached to the individual data signal words. The auxiliary information is derived from counter readings of the counter.

Abstract: A cross-connect frame for digital signals transmitted at DS-1 and higher rates independent of signal format is disclosed. In its simplest form the frame includes a single chassis into which boards providing for either a mechanical or electronically controllable connection may be inserted. In either the mechanical or electronic form provisions for monitoring and patching are included. Multiple chassis may be connected together and in the electronic form a single circuit has the capability of controlling a multiplicity of chassis.

Abstract: A method for transmitting a message by a two way wire connection between a central control and survey station (1) and several remote detection stations (3A-3N) adapted to generate a signal representative of at least one parameter of its environment, particularly for the monitoring of buildings, during which the central station (1) successively generates addresses assigned to each of the remote stations (3A-3N), these latter in response to the reception of this address emitting a message characteristic of the value of the corresponding environment parameter, characterized in that said addresses are generated by the central station (1) by modulation of a continuous voltage permanently applied to said telegraphic connection, and in that each remote station (3A-3N) transmits its message by amplitude modulation of the current on said line by application of said voltage to said line.

Abstract: A network multiple physical layer interface connected to a first communications network physical layer and through a MODEM to a second physical layer wherein the interface includes circuitry for selecting transmission and reception frequency bandwidths for the MODEM and also includes a first transceiver circuit for receiving data from the first physical layer and transmitting this data through the MODEM to the second physical layer and a second transceiver circuit for receiving data from the second physical layer through the MODEM and retransmitting the data on the first physical layer. The interface further includes user selectable modes to enable this interface to provide a communications connection to only the first physical layer or to both physical layers. Still further, the interface includes collision avoidance circuitry to prevent any transmissions onto the network through this interface when information traffic is present on either physical layer.

Abstract: Date and time information are provided in a telex and data switching system (EDS), which is connected with subscriber stations (Ttx) that are located in different time zones (ZZ1 to ZZ4). The telex and data switching system makes available a number of current date and time information items assigned to the respective individual time zones that correspond to the number of time zones to be taken into consideration. From these date and time information items there is selected, in the course of the establishing of connections, the date and time information corresponding to the subscriber stations involved in these connections, which is then made available for transmission to these subscriber stations information.

Abstract: A loop back system for a loop transmission line allows the whole system to be looped back for addition or removal of a transmission device, without cutting off loops and in exactly the same manner as in ordinary data transfer. A plurality of transmission devices capable of generating loop-back commands are connected to an active loop and a backup loop. First one of the transmission devices transmits loop-back commands, while second and third ones individually receive the loop-back commands to connect their transmitter sides to both the active and backup loops. This sets up a loop-back condition in each of the transmission devices.

Abstract: Apparatus for controlling the transfer of data between computers, connected to a communications network, accessible to at least one terminal by means of an asynchronous concentrator, which is connected between the network and an input-output junction of the terminal, comprising means connected between the input-output junction of the terminal and the concentrator, in order to asynchronously establish via the concentrator, a first virtual circuit between the terminal and a first computer of the network, then a second virtual circuit between the terminaland a second computer of the network, and connecting means for connecting the thus established virtual circuits, the transfers of files between the first and second computers then taking place across these connecting means, wherein the means for establishing the first and second circuits comprise at least one two-position switch having a common terminal member connected to the input-output junction of the terminal and two switching terminal members connected to

Abstract: The disclosure concerns a communication system for line printers, such as teleprinter equipment, via high-quality radio communications. The repetition of the signals received mutilated takes place per line of signals at the end of a number of lines. The transmitter for the system comprises a counter from which the line number is fed to the transmitter during the line printer return or the line feed period up to the end of the page or the message. The receiver detects which lines have been received mutilated and registers their line numbers. Then the request for repetition of the numbered mutilated lines is made at the end of each message and at the end of each page of the message, if the message is longer than a page, for example, 32 lines.

Abstract: Disclosed are a method and apparatus for exchanging information between a data terminal equipment (DTE) and data circuit terminating equipment (DCE) or controller connected to the data terminal equipment over a communications line. The specific information to be exchanged is the information indicating the delay period between a request to send received at the DCE and a clear to send condition occurring sometime later in response to the request to send. This function is normally handled by separate signalling lines, but for the so-called mini interface, no clear to send communication line exists. A method and apparatus employed in the present invention utilizes the transmitter signal element timing or clock line to convey the information from the DCE to the DTE. In response to receipt at the DCE of a request to send signal from the DTE, the DCE temporarily stops the transmitter signal timing clock, thus preventing the DTE from transmitting data.

Abstract: This disclosure relates to a line driver circuit for a station in a data transmission network, which driver circuit is adapted to drive the channel medium with a constant current so that conflicts or collisions with data transmissions from other stations will be cancelled out thereby preventing any particular station from dominating reception of a neighboring station. Each station is adapted to operate in a cyclic mode for contending for access to the network channel where a three-state cycle is employed, which states are the idle state, the packet-being-transmitted state and the acknowledgment period state. Each station will not begin transmission until it determines that the tunnel is in an idle state. Once the station has determined that the channel is idle, it will then delay for a period of time that is randomly chosen and, if the channel is still idle, will then begin transmission.

Abstract: A dialing system which utilizes a keypad on teleprinters retrofitted into existing teleprinter models through interfacing by voltage biasing and output circuitry with integrated circuit components having inputs to the teleprinter keypad and a pulse driver coupled to the existing dialing circuit through relays. The relays, driver and integrated circuit components are energized under different voltage levels lower than the teleprinter operating voltage through the voltage biasing circuits connected to the teleprinter power supply.

Abstract: A crypto control circuit arrangement is disclosed for controlling crypto operation in the case of procedure-controlled semi-duplex data transmission systems in which data are transmitted from a first station with a first data device and a first crypto device, via a transmission path, to a second station having a second crypto device and a second data device. The changes of the data transmission direction are signaled with an order word which is transmitted from the first crypto device to the second crypto device and is evaluated with the help of an order evaluator. A control signal is emitted at the output of the second data device which prepares the second crypto device for the transmission when an end signal is transmitted from the first data device to the second data device.

Abstract: In order to form a first-come first-served queue in an information transmission system employing a common transmission channel when several transmitters of the system try to gain access to the channel when it is already occupied, without employing a further transmission channel to a point at which an account is kept of the order in which the various transmitters request access, each transmitter which tries to gain access in these circumstances is caused to delay after the channel subsequently free before it actually accesses the channel, this delay being inversely proportional to the time the corresponding transmitter has waited. Thus the transmitter which has waited the longest gains the channel first and causes the other waiting transmitters to continue to wait.

Abstract: A system for interconnecting and switching teletypewriter or digital data gnals when transmitted over any of the four universally accepted standard signal loops. The system incorporates a novel triple loop arrangement; an "IN" loop connected to a signal source, an "INTERNAL" loop to provide switching and an "OUT" loop connected to the signal destination. Each "IN" loop or "OUT" loop together with half of its associated "INTERNAL" loop is implemented in a single printed circuit card. The system can incorporate any number of "IN" and "OUT" loops and the associated "INTERNAL" loops.

Abstract: A code generator for text transmission devices emits code characters assigned to subscribers over a trunk line in order to allow a subscriber to be recognized. The code characters are stored in a memory which is formed from electronically operable storage elements and remain unchanged following disconnection of the operating voltage. A write-in control unit is provided for writing the code characters into the memory and a read-out control unit is provided for reading the code characters from the memory. The write-in control unit can be connected by way of a line matching unit to the trunk line by way of which the texts are normally transmitted, and the code characters can be input into the memory from a central position by way of the trunk line.

Abstract: In a process for signaling an interruption in the state of readiness of a data terminal device in a called station, the data being transmitted over a data selector network, and in particular for teleprinters, following the establishment of a connection, the calling station requests the called station to transmit identification by way of the data selector network. Following reception of the identification assigned to the called station, the data transmission begins and upon the occurrence of disturbances which interrupt the state of readiness for reception in the called station, a monitoring circuit responds. For the duration of the interruption of the state of readiness the monitoring circuit blocks the identification keyer in the called station from transmitting the identification assigned to the called station and the monitoring circuit automatically clears the connection.

Abstract: A data transfer terminal of the type including a keyboard means, a display means and a printer for use in a data center controlled data transfer system. The printer of the data transfer terminal is provided with a library phrase memory. The library phrase memory contains a plurality of predetermined, commonly used phrases at various predetermined addresses in the library phrase memory. The addresses of the phrases correspond to codes which are included in messages sent by the data center to the data transfer terminal whereby the length of the messages from the data center to be printed by the printer of the data transfer terminal is greatly reduced.

Abstract: A method and apparatus are disclosed for using a specified pattern of signal events for signaling in a digital communication system. Illustratively, detection of a first event in a control signal activates timing apparatus which looks for a second event in a control signal within a specified time "window" and at least one additional event in either a data or a control signal within a specified time period. Preferably, the first event is a drop in one of the carrier detect or request to send signals and the second event is a rise in the same signal. The additional event illustratively is reception of two identical data characters, each representing an address and an operation code. Each of these two characters must be received and compared for verification within the specified time period in order to produce an output control signal decoded from the operation code.

Abstract: A closed user group facility in a data transmission system which has a closed user group of terminals accomodated in a switching network, and in which the switching network registers a terminating terminal in response to a request for registration of that designated terminating terminal from another one of the terminals. The registration of the corresponding terminating terminal is with one of codes with which all the terminals accommodated in the switching network can be individually identified. Subsequently when transmitting data (including voice data) from the originating terminal to the terminating one, the switching network controls to permit the transmission of the data from the originating terminal to the terminating one when the switching network has verified that the originating and terminating terminals had already been mutually registered as distant terminals.

Abstract: An isolated line switching circuit for direct connection of a telephone, teleprinter, or like telecommunication instrument to a transmission line, comprising a solid-state optical cell including a light-actuated optical receiver that generates an electrical current when illuminated by an associated light-emitting device (LED), and a switching transistor having its emitter-collector discharge path connected in series with the transmission line; the optical receiver is connected to the base and emitter of the transistor to drive the transistor conductive when the LED is energized by an actuation signal initiated in response to a ring signal. A high-resistance emitter-to-base circuit for the transistor drains the collector leakage current (I.sub.CBO) and maintains a high off resistance even at high temperatures.

Abstract: Ancillary equipment including a facsimile transceiver is directly connected to a telephone network through a coupling arrangement. The coupling arrangement includes a transfer relay for transferring the primary communication path to the telephone network between a telephone station set and the ancillary equipment. The transfer between the telephone station set and the ancillary equipment is controlled by a sensor which electrically senses a change from the off-hook to the on-hook state of the telephone set. The transfer is also controlled in response to the state of the ancillary equipment. The coupling arrangement also limits the signal power level coupled into the telephone network from the ancillary equipment.

Abstract: A teleprinting apparatus which eliminates a dial switch for connection to a remote subscriber and which substitutes a circuit arrangement which utilizes the keyboard through a coding system to generate pulse trains for connection to the remote subscriber. A selection pulse generator is set in operation by a "proceed to select" signal which is supplied with signals emitted by a keyboard and derived from a counter pulse train of constant repetition frequency. In this way selection pulses are produced, the number of which is determined by the key which is being operated. The number is actually fixed by the use of a comparator which compares the keyboard signal with the output of a counter which is counting the pulse train.

Abstract: In a multi-device data transmission system with source and acceptor devices linked by a data highway and handshake lines, provision is made for automatically adjusting the delay of the handshake cycle to suit the highway length and other determinative factors. This is achieved in that the acceptors do not accept data until told so to do via one handshake line, whereas the source is only allowed to issue this command when it has been told via another handshake line that all acceptors have seen the data. The system determines its own delay in this way and automatically adapts the delay to whatever length of highway is employed, whether a fraction of a meter in a circuit board or several tens of meters in inter-rack wiring.

Abstract: An arrangement for synchronizing one or more input/output devices in teleprinters in the context of a subdivision, necessitated by the use of a five-bit code (CCITT 2) for communications transmission purposes, of the total quantity of characters into letters/figures levels employs a storage device in which the level relationship (letters and figure levels) of the character last transmitted or received is stored. A comparator connected to the storage device compares the level relationship of the stored character with that of a character ready for transmission and in the event of disparity operates, via a logic arrangement, to effect the introduction of a level-related switching symbol.

Abstract: A code generator for teleprinters or data printers which, for the recognition of the subscriber, emits a sequence of character signals assigned to the subscriber. A memory is provided which is constructed from electronically operable storage elements in which the character signals are stored and are not altered after the disconnection of the operating voltage. Registers are provided which contain the addresses of the particular operated storage elements and a read-out control unit is provided by means of which the character signals are read out from the storage elements.

Abstract: Power lines within a building or other user location are connected through a fuse and a filter to an external power grid that supplies power at the usual 50 Hz or 60 Hz. Communications apparatus such as a central computer and a number of typewriters is connected to the power lines within the building at at least two locations and transmits communications signals over the power lines. The communications signals have a frequency different from the frequency of the electrical power supplied by the external power grid and preferably in the audio range. The filter is tuned to pass the electrical power but substantially to block passage of the communications signals. Two important advantages are that the power lines within the building double as communications lines and that the building presents a purely resistive load to the external power grid, so that the grid has an improved power factor.

Abstract: A steno transtator system for translating stenographic keystrokes to language format according to a predefined keystroking methodology includes a steno writer to generate a sequence of stroke symbols each having associated therewith language parts consisting of suffixes, prefixes, word parts, punctuation and language symbols. A processor is coupled for receiving the stroke symbols and includes memory for storing a list of stroke entries, each represented by at least one stroke symbol, and an associated language part defining the translation for that stroke entry. The stroke entries are arranged in the memory in accordance with the predefined stroke entry order. The processor also includes a translator for segmenting the sequence of stroke symbols into a plurality of consecutive subsequences where each of the subsequences includes at least one stroke symbol and has a corresponding matching stroke entry in the memory.