Abstract: A connector block including a built in test device for testing a pair of wires connected to the block. The connection block includes a first terminal that is connected to a first one of the pair of wires and a second terminal that is connected to a second one of the pair of wires. A test board is slideably mounted on the connector block for slideable movement between a test position and an inactive position. A current indicator is disposed on the test board so that when the test board is in the test position, the current indicator forms an electrical connection between the first terminal and the second terminal indicating the presence of an electric current.

Abstract: A grievance call processing system capable of automatically shifting a grievance call reception state to a test state. An electronic switchboard notifies the telephone number information of a subscriber to a workstation, which stores and displays the telephone number information. When a maintenance person makes a test activation from the workstation upon reception of a grievance call the telephone number information is simultaneously and automatically notified to a testing trunk, which provides the telephone number information to the electronic switchboard, which then sets up a testing path from the workstation to a subscriber testing equipment through the testing trunk for the preparation of a subscriber test state.

Abstract: In a method of administering a telephone local loop plant, a substantial portion--preferably at or above 80%--of the existing narrowband plant is caused to be "dedicated," so that constituent segments of an existing local loop therewithin are not allowed to be used to form other local loops when the existing loop is taken out of service. The remainder of the narrowband plant--the "non-dedicated" plant--is used to fill subscriber current orders for new service. Administration of the narrowband plant that has been dedicated is given over to an administrative system that is deployed to administer broadband facilities within the local loop plant. In preferred embodiment, the local loop plant is upgraded from narrowband to broadband in a way which gives priority to those geographical areas for which the costs of maintaining the narrowband plant are the greatest. The method, overall, provides a mechanism for reducing the costs associated with administering all of the narrowband plant using the legacy systems.

Abstract: In a computing network environment having a gateway device that is connected on one side to at least one local area network and on other side to a plurality of initiating hosts, a method of establishing direct communication between a first initiating host and a second initiating host through the gateway device without necessity of involving the local area network in this communication and its related data transmission. The method comprising the steps of first obtaining the addresses and information of all connected hosts needed for establishing communication and storing it in a memory location accessible to said gateway device in form of a port-sharing table. The gateway device will be handling all requests for communication setups between hosts.

Abstract: A computer system comprises a plurality of user computers interconnected through a public-switched telephone network and trunk lines, and also includes a plurality of Remote Data Processing Nodes (RDPNs) similarly connected to each other and to the user computers. A BBS station which is also coupled to the network receives test data from the user computers. Each user computer includes a test unit that includes a digital signal processor and an active control unit. The test unit has a dialing directory for connecting to various BBSs to test out the communication through a modem and the telephone network. Using the dialing directory, the test unit activates the modem to make a predetermined call through the telephone network to several of the RDPNs. The test unit collects survey, snapshot and real-time data packets in a predetermined data file which are communicated to the BBS station for debugging the system and determining the performance of the system.

Abstract: A signaling test apparatus for testing a trunk register transmitting/receiving signaling, a subscriber service signal tone, a subscriber DTMF transmitting/receiving signaling, and a CCT transmitting/receiving signaling in a switching system. The signaling test apparatus includes a computer interface for communicating with a computer, a PCM interface for communicating with the switching system, a microprocessor for receiving a test command transmitted from the computer through the computer interface and generating a control signal to perform a corresponding test mode, a test signal storage memory for supplying a plurality of test signals having a predetermined frequency to the switching system through the PCM interface under the control of the microprocessor, and a digital signal processor for analyzing the test signal which is fed back from the switching system and received through the PCM interface under the control of the microprocessor.

Abstract: In a telecommunications system, the amount of time a subscriber device is effectively out of service as a result of some fault or failure in telecommunications equipment is monitored. Subscriber devices are connected by corresponding subscriber communication paths to receive information from or transmit information to a telecommunications center such as a local telephone exchange. One or more data records is maintained in computer memory for each subscriber path connected to the communications center. Each data record is updated using recently determined data relating to the operational status of each subscriber path. The computer then determines from the updated record in accordance with one or more subscriber line blocking criteria a subscriber path blocking parameter. The subscriber path blocking parameter may represent for example an average amount of time each subscriber path satisfies the one or more subscriber line blocking criteria.

Abstract: A method for detecting improper delivery of parameters in an initial address message (IAM), such as a calling party number (CPN), for calls set up to a switch over SS7 trunk groups connected to other carriers is described. When a call originates from a switch other than the local switch serving a caller ID customer, the CPN should be passed, as a parameter in a call setup message called an Initial Address Message (IAM), from the originating switch to any intermediate switches, and from those intermediate switches to the customer's terminating switch. The method allows a switch to reliably and proactively identify when an IAM parameter, such as CPN, is not being received (and should be), from an interconnecting switch, for calls over specific TSGs connecting two switches.

Abstract: An electronic switching system having a plurality of processors connected to an internal switching network in a chain structure of a linked list form and a maintenance processor for checking status of each individual processor connected to the internal switching network. The status of the processors is checked through a mutual status checking process between unit processors, and if any processor contains any abnormality, such abnormal status of the processor is notified to the maintenance processor.

Abstract: A communications networking system is disclosed for controlling and monitoring devices within a telephony central office. The networking system includes a high bandwidth local area network (LAN) within the central office for transferring substantially all communications between each central office network element and remote telephony operational support systems (OSSs) that control and monitor network element performance. The LAN simplifies communications within the central office: (a) by substantially eliminating direct connections, between central office network elements and remote OSSs, and (b) by utilizing at least one standardized communication protocol such as TCP/IP, UDP/IP, or OSI when transferring communications over the LAN. The networking system includes a mediation device(s) for translating between network element specific protocols and a standardized protocol used on the LAN.

Abstract: A telephone call on a remote line (190) is initiated by establishing a simultaneous voice and data connection with a slave processor (180) tied to the remote line. The slave processor is responsive to commands received on the data connection, including an off hook command signaling the slave processor to go off-hook on both the voice connection and remote line. Thereafter, the slave processor (180) bridges the voice connection and remote line. Upon receipt of the digits of a telephone number entered on the voice connection, the slave processor, in turn will dial the digits on the remote line, thereby initiating a call on that line.

Abstract: A system and method are provided for providing non-disruptive diagnostics between a first device and a second device in communication through a virtual circuit of a frame relay network. In accordance with one aspect of the invention, the method defines a diagnostic channel by assigning it a unique channel address, transmits a test command from the first device to the second device across the unique channel address, monitors the unique channel address for a response to the test command, and then evaluates the response to determine whether it reflects a fault in the virtual circuit. In accordance with one embodiment, the test command could be a pattern message, a connectivity request, a start send pattern command, a start loopback command, a start monitor pattern command, and a start send pattern command.

Abstract: A system and device for, and method of, detecting, characterizing, and mitigating deterministic distortion in a communication system. An exemplary communication system includes a digital adaptor for sending octets on to a backbone of a PSTN, which then sends, and potentially distorts the octets, received by a line interface. The line interface converts the octets to baseband signals received by an analog adaptor. Several mechanisms and methods are described in which the analog and digital adaptor cooperate to detect the presence of distortion, in particular, robbed bit signaling, on the communication system. The characterization may then be used to mitigate the effects of the distortion. Several receive constellations are provided, each constructed in view of the transmit constellation and in view of the manner in which the deterministic distortion will distort signals transmitted over the system. The receive constellations differ from the transmit constellation.

Abstract: A method for monitoring the signaling network in a telecommunication system comprises extending a copy of each signaling message processed by a particular signal transfer point to an interface unit. The interface unit relays "of interest" messages to a signal monitoring system (SMS) in accordance with a pre-determined filtering protocol. In the SMS, messages are correlated in accordance with a pre-defined correlating protocol. The correlated signaling messages are subsequently retrieved by an OSS technician for analysis and updates.

Abstract: An interconnection monitoring system for use with a multiple node wired network, the system comprising a plurality of transmitters, each located at a node of the network for transmitting a transmission from the node and a plurality of receivers, each located at a node of the network, for receiving a transmission at the node, the plurality of transmitters being operative to transmit along the network a signal bearing an identification code identifying the node from which a transmission takes place, the plurality of receivers being operative to receive transmissions from a plurality of nodes, bearing the identification codes and thus indicating the interconnection status of the nodes.

Abstract: A testing device to close a circuit between first or second sections of a pair of lines within a connector block in which the first and second sections of each line are normally connected by pairs of connector parts with which the sections of the lines are connected, a socket opening at each connector part and pairs of electrically connected contact prongs removably engaged in the socket openings, the testing device includes a manually engageable case carrying two prongs have free ends projecting therefrom and a bridge line within the case and connecting the prongs, the two prongs of the device are selectively removeably engageable in the socket openings related to the connector parts with which the first section the two parts are connected and in the socket openings related to the connector parts with which the second sections of the lines are connected.

Abstract: A test interface adapter allows a line-conditioning or test device, such as a direct access test unit (DATU), that is normally interfaced with a standard central office switch via a no-test trunk, to be coupled to and communicate with the respective ports of a test interface of a non-standard central office switch that is not equipped with a no test trunk, so that conditioning and/or testing of subscriber telephone lines served by such non-standard central office switch may be carried out. When so installed, the interface adapter of the present invention is operative to map signals at first interface ports, to which the non-standard central office switch is connected, to second interface ports to which the line conditioning/test device (e.g DATU) is connected, and vice versa.

Abstract: A method and connectivity evaluation system for testing trunk lines dedicated by a centralized telecommunications system to a customer switching system, such as a PBX, includes allowing the trunk-seizing capability of the telecommunications system to be remotely accessed from the premises of the customer switching system. The dedicated trunk lines can be sequentially isolated in response to the remote access of the trunk-seizing capability. Isolated trunk lines can be used to transmit test signals to opposite end equipment for evaluating characteristics of the signal. The test signals can be generated from either or both of the central office of the telecommunications system and the premises of the customer switching system, but in the preferred embodiment, all such transmissions are controlled from the customer switching system. In another embodiment, the transmissions are controlled from the central office.

Abstract: A method and related system dynamically determines the location of a network outage in a telecommunications network. A plurality of alarm generating network equipments are located at spaced sites along the network. Alarms are generated upon the detection of problems with a signal passing through continuous signal trunks connected between the alarm generating network equipments. The alarm data from the alarm generating network equipments is connected at a single point. Network topology data is stored in a database, defining the relative locations of the alarm generating network equipments in the network and their respectively connected trunks. The alarmed equipment ports are correlated with respective connected alarmed trunks from data obtained in the database as well as collected alarm data. The alarmed trunks are analyzed for identifying the corresponding minimum number of alarm generating network equipments that exist between the alarmed trunks thereby defining effected inter-equipment trunks.

Abstract: An electronic private branch exchange includes a first fault detection portion, a first alternate control portion, a second fault detection portion, and a second alternate control portion. The first fault detection portion detects occurrence of a fault on a private line for connection to a remote electronic private branch exchange (EPBX). The first alternate control portion selects one of a plurality of integrated services digital network (ISDN) lines registered in advance after the first fault detection portion detects occurrence of the fault, thereby forming a first alternate communication path for alternate connection to the remote EPBX. The second fault detection portion detects occurrence of a fault on a first alternate line formed by the first alternate control portion.

Abstract: A method for identifying damaged cable pairs in a pulp cable comprises arbitrarily attaching proximal ends of damaged cable pairs to ports on a first connector block of a service restoration system (SRS), and arbitrarily attaching distal ends of damaged cable pairs to ports on a second connector block of the SRS. Directory number information associated with each damaged cable pair is retrieved by the SRS from affected subscribers, and the serving switch. If a match of directory number information is found, the proximal damaged cable pair end is interconnected to the distal damaged cable pair end of a single cable pair via SRS switch fabric. The SRS periodically generates a status report including port locations of corresponding ends of a damaged cable pair so that the ends may be permanently spliced together.

Abstract: An enhanced ISDN-DP transmission device of the present invention allows for testing of ISDN-protocol communication paths using an existing DDS-protocol test infrastructure. The ISDN-DP unit receives a DDS test command and determines whether the command was intended for the immediate receiving unit or a tandem unit. If the command is intended for the immediate ISDN-DP unit, the unit processes the command. If the command is intended for another ISDN device in the transmission path, the ISDN-DP converts the DDS-protocol command to an ISDN-protocol command and transmits the converted ISDN command to an adjacent tandem ISDN device in the communication path in an upstream or downstream direction. After the test path is enabled, loopback testing is available on all available ISDN bandwidth, including the B1, B2 and D+ channels, from a DDS-protocol test set.

Abstract: A method and apparatus for monitoring the status of a speech connection between central office lines in a private exchange system may be constructed with a controlling unit for controlling a connection between a network and a corresponding central office line to perform a speech connection between first and second central office lines; a line interface unit for interfacing the first and second central office lines under the control of the controlling unit; a network unit for connecting the first and second central office lines to each other under the connection control of the controlling unit; and a speech monitoring the status of unit for monitoring the speech connection during the connection of the first and second central office lines, by directly detecting the presence or absence of a signal from the first and second central office lines inputted thereto through the network unit without interrupting the connection between the first and second central office lines and for outputting the speech connection s

Abstract: A communications networking system is disclosed for controlling and monitoring devices within a telephony central office. The networking system includes a high bandwidth local area network (LAN) within the central office for transferring substantially all communications between each central office network element and remote telephony operational support systems (OSSs) that control and monitor network element performance. The LAN simplifies communications within the central office: (a) by substantially eliminating direct connections, between central office network elements and remote OSSs, and (b) by utilizing at least one standardized communication protocol such as TCP/IP, UDP/IP, or OSI when transferring communications over the LAN. The networking system includes a mediation device(s) for translating between network element specific protocols and a standardized protocol used on the LAN.

Abstract: A method of and system for managing telecommunications system testing. The system displays a list of available originating and terminating bulk call generators. The user can graphically select the bulk call generators to be used in the test and can communicate with selected bulk call generators through the interface. The system also displays a list of available test case scripts. The system enables the user to formulate a mix of scripts to be executed by displaying a control for each selected test case script. The system further enables a user to designate different mixes of scripts for selected time periods over a test run. The system then assigns each script to a call program and a group of call programs to a set. The system then starts the set at the user predefined time. The system the stops the set and resets each call program and set based on the previously chosen call mixes.

Abstract: A voice monitoring method which is capable of preventing an occurrence of the interruption of a call and reducing the burden of switching software, and also capable of monitoring the contents of a call whose communication path is performed within the same line switch installed in a remote place is provided. A voice from a monitored subscriber telephone set 6-1 is distributed at a line switch 4-1 to a voice monitor path (unidirectional path) 8-1, and a voice from a subscriber telephone set 6-2 of the other party is distributed at the line switch 4-1 to a voice monitor path (unidirectional path) 8-2. The distributed voices are given through a time-division switch 3 to the first and second terminals of a three-way trunk 5, are mixed at the three-way trunk 5, and are sent through the third terminal to a monitor telephone set 7.

Abstract: A modular switch box which is responsive to a control signal, is diagnosable, and is not dependent upon the type of protocol being switched. There may be a plurality of switch boxes wherein each switch box includes a plurality of inputs and an output. There is a selector for selecting which input is connected to the output and a controller for controlling the selector. There is also a control means for controlling the switch boxes. The switch boxes are connected in a chain so that the input of one switch box is connected to the output of the next, etc., until the output of the last switch box is connected back to the controller. The controller sends a command message to the first switch box which then executes the command and forwards the message on to the next switch box, etc., until the command returns to the controller. In this manner, the controller knows that all switch boxes have received the command.

Abstract: A test interface adapter allows a line-conditioning or test device, such as a direct access test unit (DATU), that is normally interfaced with a standard central office switch via a no-test trunk, to be coupled to and communicate with the respective ports of a test interface of a non-standard central office switch that is not equipped with a no test trunk, so that conditioning and/or testing of subscriber telephone lines served by such non-standard central office switch may be carried out. When so installed, the interface adapter of the present invention is operative to map signals at first interface ports, to which the non-standard central office switch is connected, to second interface ports to which the line conditioning/test device (e.g DATU) is connected, and vice versa.

Abstract: A system and method for reconfiguring a validation system in real time is presented. An operator console receives a call having one or more pieces of information that are to be validated. The operator console sends a validation request to a validation system. The validation system includes a database that stores instructions that define at least a part of a validation procedure corresponding to the validation request. The validation procedures can be changed in a manner transparent to the operation of the operator console.

Abstract: The disclosed facility type determination technique ascertains whether or not a facility connection is solely digital. In the disclosed embodiments, this information is used to establish the rate at which data is coupled through the facility connection. More specifically, a predetermined test signal including a pseudorandom sequence of digital signals is transmitted through the facility or combination of facilities connecting a data source to a data destination after the connection between the source and destination is established. The received test signal is examined at the destination and the examination results are used to determine the rate at which data is subsequently transmitted between the data source and data destination. Advantageously, this technique does not restrict network facility management and can be employed in a variety of data communication applications.

Abstract: A transmission system provides a stand-by line switching facility. The transmission system includes a plurality of working line side processing equipments and a stand-by line side processing equipment to replace one of the working line side processing equipments if a fault occurs therein. The transmission system has a first unit and second unit disposed for each working line side processing equipment. The first unit issues, upon receipt of a line switching command, a single line switching control signal. The second units commonly receive the single line switching control signal and respective line switching is performed between the faulty working line and the stand-by line simultaneously.

Abstract: Connection is made directly or via a switched telephone network between a tester and a telecommunication system to be tested. User data, such as voice signals, and signalling data, such as DTMF signals are generated by the tester to cause the telecommunication system to respond. The user and signalling data may be generated interactively to test the telecommunication system in real time, or by executing prerecorded scripts. When the tester is used interactively, the representations of the signals transmitted to and from the tester are recorded in at least one script file. Voice recognition is preferably used to determine whether the response received from the telecommunication system is the expected response, particularly when a script is executed. The vocabulary used for voice recognition may be created by repeatedly executing a script file (recorded during interactive operation of the tester or created manually) which causes the telecommunication system to generate the desired prompt(s) and message(s).

Abstract: A DS3 level access, monitor and test system for a telephone network. The system provides selective, and hitless, bit overwrite in any of the embedded DS1, DS0 and subrate channels in a DS3 signal. Multiple DS0 and subrate channels can be tested via the asynchronous time slot interchange in conjunction with the recombiner of the present invention. A second embodiment of the invention partitions the system into a base subsystem, a communications link and a remote subsystem, collectively referred to as a distributed architecture system. The distributed architecture system provides all of the performance monitoring and testing capabilities of the existing access system. The distributed architecture system provides a mechanism to transport a plurality of asynchronous and rate independent signals across the link to permit remote testing of digital and voice DS0 frequency circuits. In the preferred embodiment, the link that connects the base to the remote system is a standard DS1 channel.

Abstract: A method for providing switch translations upon a failure in the conventional recent change message handling system. The failure results in triggering a common channel signaling inquiry, to a signaling control point which responds with instructions for setting up a common channel signaling link between the Recent Change Memory Administration Center (RCMAC) to an alternate Remote Memory Administration System (RMAS). The RCMAC then delivers the recent change message to the alternate RMAS and the RMAS delivers the recent change signal to the addressed switch. In an alternate embodiment the Signal Control Point is provided with RMAS capability. This RMAS capability is then used in place of the alternate RMAS and the SCP sets up a path from the SCP associated RMAS to the RCMAC and to the addressed switch. The communication from the RCMAC which initiated the inquiry to the SCP and RMAS associated therewith is in common channel signaling protocol.

Abstract: A switchable order wire circuit installed in addition to a trunk connecting a master station which includes an exchanger and a dependent station in a telephone system. The order wire circuit includes a first telephone terminal located in the master station, a second telephone terminal located in the dependent station, and a pair of telephone lines connecting the first and second telephone terminals. The order wire circuit also includes a hooking detection system installed in the master station, for detecting a hooking operation of the second telephone terminal. In addition, a circuit for switching the telephone lines from the first telephone terminal to a public line when the hooking operation is specifically detected is included.

Abstract: An automatic circuit back-up system is adapted to a data communication system including a private communication line for data communication and a back-up communication circuit for providing a back-up for the private communication circuit. The automatic circuit back-up system includes a periodic message transmitting circuit for transmitting a periodic message at a predetermined regular period to a distant office through the back-up communication circuit, and a monitoring circuit for monitoring whether the periodic message transmitted from the distant office via the back-up communication circuit is received at the predetermined regular period.

Abstract: A communication network signalling system couples a signal transfer point to a plurality of channel banks through links which include link monitor and test units. The link monitor and test units, which monitor the links in a passive, non-obtrusive manner and which at the same time are capable of being serially coupled into the link so as to insert signals in series with the link and to otherwise accomplish in-depth link testing and analysis, each include a pair of channel units coupled to opposite portions of an associated link and which are coupled together through a metallic through connection in the form of a normally unenergized relay. The metallic through connection provided by the relay maintains the signal path through the link during a variety of fault conditions, while at the same time permitting electronic portions of the channel units to be cross-connected to accomplish monitoring and testing functions.

Abstract: A method and apparatus for determining whether a telephony system malfunction is caused by defective telephone company trunk lines connected thereto, or caused by defective system equipment. The present invention comprises two double pole double throw relays having connections arranged whereby a pair of telephony equipment interface channels have multiple remote testing capabilities. The present invention performs trunk rolling and/or inter-channel loop back testing under local or remote control.

Abstract: A plurality of telephone devices responsive to computer commands are connected to a telecommunications switch. A computer controlled apparatus sends command messages to the telephone devices causing them to initiate conventional actions such as dialing. The apparatus receives reply messages from the telephone devices which represent the status of parameters such as ringing associated with the telephone device. Reply messages are identified relative to previously sent command messages. If the actual status of parameters represented by a reply message matches an anticipated status of the parameters corresponding to actions expected in response to a command message, a successful test of the switch functions associated with the command message results. An unmatched condition corresponds to a test failure requiring user analysis.

Abstract: A telecommunications network testing and protocol analyzer arrangement including an improved control and port selecting circuitry which may be provided in the form of a board which plugs into a standard IBM or IBM compatible PC, XT, AT expansion bus (8 bits) and allows for the operate, non-operate control of up to 180 port relays while at the same time providing 8 simultaneous control outputs for other circuit and parameter control functions. All outputs are standard TTL level outputs which may be directly utilized as relay drivers. The selector and control board is controlled by software running under standard PC DOS of MS DOS. The control and selector board may be controlled completely from the computer keyboard as well as from a remote IBM or IBM compatible computer.

Abstract: An order wire device in a communication system having a plurality of order wire devices, signals output from each of the order wire devices being serially transmitted to remaining order wire devices, each of the order wire devices being capable of simultaneously calling remaining order wire devices in an all station calling mode.

Abstract: An automated translation input system to convert Mechanized Translation System (MTS) orders into Recent Change Messages that can be loaded into a program controlled switch without enhancement or changes in the MTS program to provide a significant saving in Switching Control Center (SCC) labor hours. The new system and method permit using the output of the MTS which would otherwise constitute a printed form for inputting the Automated Translation Input System (ATIS) where the forms are analyzed, the associated Recent Changes are analyzed, and the Recent Change Messages are prepared. The thus prepared Recent Change Messages are inspected by the SCC technician who, through a manual option in the ATIS system, gives the command to download the translations directly into the switch. This eliminates the need for key preparation of the Recent Change forms by the SCC technicians and results in an elimination of keying errors and a significant saving in time.

Abstract: In order to back up by an ISDN line two analog lines connected to MODEM of a four wire full duplex type for data transmission and reception, a terminal adapter is connected to a pair of back-up ports. Dial pulse signals delivered through the back-up ports are detected and converted into an ISDN telephone number. A D-channel processor performs the call connection by use of the D-channel signal having the ISDN telephone number and an identifier of a particular one of B-channels. An outgoing analog data from the MODEM through one of the back-up ports is A/D converted and then transmitted on the particular B-channel to the ISDN line. An incoming digital data on the particular B-channel signal received at the terminal adapter is D/A converted and is supplied to the MODEM through the other of the back-up ports. Thus, the back-up is performed by use of a single B-channel on the ISDN line.

Abstract: A power seat apparatus which comprises motors for moving a seat in respective direction, relays for changing rotational directions of the respective motors, a preset memory for memorizing a seat position suitable for respective drivers, a memory drive circuit for driving the motors so as to move the seat into the memorized position automatically according to data memorized in the preset memory, a manual drive circuit for driving the motors according to an operation of a manual switch and a control mechanism. The control mechanism detects the contact fault in the relays, or controls the motors accurately by counting the number of inertial rotations as a proper directional rotation without misjudgement even if the manual switch is operated in the reverse direction when the motors are driven automatically in one direction.

Abstract: Each wire of a subscriber's line is connected to its associated input of a subscriber's line unit by two interconnected relay contact sets. The relay contact sets are also connected to test busses. If a subscriber's line unit becomes faulty, a spare subscriber's line unit can be switched in to replace the faulty unit. The connection path is made by way of the test busses and the relay contact sets associated with the respective units. Test access paths may also be provided from the busses to the units.

Abstract: A method for error-protected switching operation of switching devices of a high-voltage switching station. The current operational state of the station is determined from the signals provided by position indicating contacts (K.sub.I, K.sub.II, K.sub.III) of the switching devices. Using the obtained operational state, switching operation request commands (for example KA) are checked for release or blocking status by means of error-protected switching interlocking rules. In the case of changes in the topological configuration of the high-voltage switching station and/or in the case of changes of the error-protected switching interlocking rules, it is possible to adapt the basic method to these changes in a simple manner and without losing operational reliabilty. This is achieved by decoupling the topological configuration of the high-voltage switching station from the error-protected switching interlocking rules.

Abstract: An electronic switching network for use as a transit exchange, interconnects PCM digital trunks, and handles large numbers, e.g. 1,000 inlets and 1,000 outlets of such trunks. The switching network is fully electronic, using integrated circuit units. To provide a self-checking function, the intelligence arriving via the trunks is converted (2) into a redundant line code, e.g. 3B-6B, which has spare code combinations which are used to provide an auxiliary data channel through the switch matrix (3). The converter (2) applies to that data channel the inlet port number for a connection via the switch matrix (3). At the outlet side another converter (4) converts back to the line code (e.g. HDB-3) used over the trunks, and also extracts the inlet port number. This is then compared with what it should be, and the result of this comparison indicates whether the switch is functioning correctly. Thus the checking occurs while the switch is handling traffic.

Abstract: An apparatus and method for accessing communication systems includes a microprocessor for controlling said accessing. Communication line access is accomplished by an interface with test trunk equipment and MDF shoes. Capability for generating dial pulse, DTMF and multifrequency dialing signals is included. Communications components and a test bus permit the apparatus to interface with a supervisor unit and a testing unit.