Abstract: In a stored program controlled electronic telephone switching system transmission links are provided from a host office, provided with a central processor, to one or more remote offices, each provided with a remote processor. Data and control information are continually passed between the host office and each remote office in a digital time-division format. Data integrity is monitored through a cyclic odd and even patterned parity scheme which predetermines the parity of sequential time slots in one direction of transmission and reflects that parity pattern in the return direction of transmission between host office and remote offices. The patterned parity scheme detects hardware faults in the interface for the transmission links between host and remote offices on a continuous basis.

Abstract: A mechanized system distributing the access, test and communication functions to the point of testing, typically the centralized switching facility serving the telephone loops and equipment to be tested. Computer (200) stores information about each subscriber loop in the geographical area served by a system. Front-end computers (220,221) interact with computer (200) to retrieve pertinent data regarding loops to be tested. Each switching facility in an area includes a loop testing system (e.g., 160) that implements the required functions. The communication functions residing in front-end computers (220,221) and loop testing systems (160,161) are coupled via a data communication network (140) in a manner that allows any front-end computer to communicate with any loop testing system. Users of the system control access and test from consoles having the capability of establishing independent communication paths over the national dial network for interactive tests on loops accessed through standard test trunks.

Abstract: A mechanized system distributing the access, test and communication functions to the point of testing, typically the centralized switching facility serving the telephone loops and equipment to be tested. Computer (200) stores information about each subscriber loop in the geographical area served by a system. Front-end computers (220,221) interact with computer (200) to retrieve pertinent data regarding loops to be tested. Each switching facility in an area includes a loop testing system (e.g., 160) that implements the required functions. The communication functions residing in front-end computers (220,221) and loop testing systems (160,161) are coupled via a data communication network (140) in a manner that allows any front-end computer to communicate with any loop testing system. Users of the system control access and test from consoles having the capability of establishing independent communication paths over the national dial network for interactive tests on loops accessed through standard test trunks.

Abstract: A mechanized system distributing the access, test and communication functions to the point of testing, typically the centralized switching facility serving the telephone loops and equipment to be tested. Computer (200) stores information about each subscriber loop in the geographical area served by a system. Front-end computers (220,221) interact with computer (200) to retrieve pertinent data regarding loops to be tested. Each switching facility in an area includes a loop testing system (e.g., 160) that implements the required functions. The communication functions residing in front-end computers (220,221) and loop testing systems (160,161) are coupled via a data communication network (140) in a manner that allows any front-end computer to communicate with any loop testing system. Users of the system control access and test from consoles having the capability of establishing independent communication paths over the national dial network for interactive tests on loops accessed through standard test trunks.

Abstract: A mechanized system distributing the access, test and communication functions to the point of testing, typically the centralized switching facility serving the telephone loops and equipment to be tested. Computer (200) stores information about each subscriber loop in the geographical area served by a system. Front-end computers (220,221) interact with computer (200) to retrieve pertinent data regarding loops to be tested. Each switching facility in an area includes a loop testing system (e.g., 160) that implements the required functions. The communication functions residing in front-end computers (220,221) and loop testing systems (160,161) are coupled via a data communication network (140) in a manner that allows any front-end computer to communicate with any loop testing system. Users of the system control access and test from consoles having the capability of establishing independent communication paths over the national dial network for interactive tests on loops accessed through standard test trunks.

Abstract: A mechanized system distributing the access, test and communication functions to the point of testing, typically the centralized switching facility serving the telephone loops and equipment to be tested. Computer (200) stores information about each subscriber loop in the geographical area served by a system. Front-end computers (220,221) interact with computer (200) to retrieve pertinent data regarding loops to be tested. Each switching facility in an area includes a loop testing system (e.g., 160) that implements the required functions. The communication functions residing in front-end computers (220,221) and loop testing systems (160,161) are coupled via a data communication network (140) in a manner that allows any front-end computer to communicate with any loop testing system. Users of the system control access and test from consoles having the capability of establishing independent communication paths over the national dial network for interactive tests on loops accessed through standard test trunks.

Abstract: A mechanized system distributing the access, test and communication functions to the point of testing, typically the centralized switching facility serving the telephone loops and equipment to be tested. Computer (200) stores information about each subscriber loop in the geographical area served by a system. Front-end computers (220,221) interact with computer (200) to retrieve pertinent data regarding loops to be tested. Each switching facility in an area includes a loop testing system (e.g., 160) that implements the required functions. The communication functions residing in front-end computers (220,221) and loop testing systems (160,161) are coupled via a data communication network (140) in a manner that allows any front-end computer to communicate with any loop testing system. Users of the system control access and test from consoles having the capability of establishing independent communication paths over the national dial network for interactive tests on loops accessed through standard test trunks.

Abstract: A status report of equipment in a telecommunications network is transmitted automatically from the equipment to the network maintenance center. The status report includes information such as the serial number of the equipment and its location. Based on such a status report, the network maintenance center can keep up-to-date records of where equipment is located, how the equipment is interconnected with other components, and whether that equipment is functioning correctly. Furthermore, a portable test device can be used by a maintenance person to read the status report transmitted on the line and thereby determine the end points of any transmission line.

Abstract: A first-in, first-out queue has a random access memory (RAM) for storing a plurality of information words, seriatim. A controller is used to insure that only after a complete message, comprising the information words, has been received will a word of that message be read out. Three pointers are used to effect this result. A read pointer addresses the location in the RAM from where a word may be read. A write pointer addresses the location in the RAM where a word may be entered. A third pointer addresses the location in the RAM where the last word of a complete message is stored.

Abstract: A method for analysis of rotary dial pulses focuses on transitions between pulse levels and differentiates true level changes from noise using a procedure employing two sample counters. One counter registers the number of consecutive samples at either the high or low levels and, once a predetermined number of consecutive samples are detected, a corresponding high or low level is declared. However, since noise may influence the detection, the total number of samples, from the first indication of a level change until the declaration of a state, is maintained in a second counter. A false transition reinitializes both counters, while level changes yielding less than the predetermined number only reinitialize the first counter.

Abstract: Method and apparatus for the rapid generation of discrete random variates, of a general probability distribution, from random variates of a uniform distribution uses simple logic and moderate storage requirements. Access to a first table at an address which is a function of a uniform variate gives the desired variate value directly for a large percentage of cases and in the remaining cases the desired variate value is obtained by an indexed search of a second table of cumulative distribution function values. Results of greater precision are realized in faster execution times with less logic complexity and reduced storage bulk as compared with prior methods and apparatus.

Abstract: Messages, comprising a plurality of multiplexed packets of information bits, are received on a transmission line from each of a plurality of sources. All packets from the same source have the same source identification number and are stored in one of a plurality of first-in, first-out queues. After at least one of said packets has been stored, it is available for being read out from the first-in, first-out queue. In order to insure that each queue has an equal chance of being accessed by a utilization means, the status of all queues is registered in a status register.

Abstract: A balanced modulator, producing a double sideband suppressed carrier (DSBSC) output achieves carrier suppression and linear performance suitable to modulate frequency division multiplexed signals with stringent interchannel interference requirements. It is simply and inexpensively realized through the use of two logic gates which are arranged in a dual complementary fashion, so that their output terminals go high and low alternately, and which drive a center-tapped transformer through coupling capacitors to provide the required switching function necessary to produce the DSBSC output. The modulator circuit has the added feature that the square wave carrier source that is applied to the logic gates can be the means of activating the circuit, thereby eliminating the need for a separate power supply.

Abstract: Methodology, and associated circuitry, for encoding and decoding data words to provide burst error correction capability are disclosed.Encoder (14): partitions the data words into a plurality of subrate streams; individually codes these streams utilizing a block coding technique; and then recollates the coded streams as well as the associated parity words in an interleaved order to produce the encoder output.Decoder (20): partitions the received words into a corresponding plurality of subrate received streams; individually computes the syndrome as well as shifted and divided versions of the syndrome for each received stream; after each shift and divide, compares the partial remainder with the applicable code characteristic polynomial; and corrects the applicable bit in the corresponding received subrate stream whenever the comparison indicates an error has occurred.

Abstract: In order to insure continuous access to diagnostic and maintenance information from a computer, the console port of the computer is connected either to the console locally or to a terminal remotely. In response to an activating command from the remote terminal, a switch is operated to disconnect the local console from the computer and another switch is operated to connect the remote terminal to the computer.

Abstract: A transmission system comprises apparatus for the transmission of voice signals only, data signals only, or a combination of both voice and data signals in a multiplexed stream of eight bit time slots over a single, bidirectional digital channel for a point-to-point connection. In the combined mode, the encoded voice signals, using low bit rate voice encoders, are assigned to four bit positions of the eight bit time slot; the data signals are assigned to the remaining four bits. Up to two bit positions normally used for data may be used for signature bits, thereby identifying whether the multiplexed stream comprises voice signals only, data signals only, or a combination of both voice and data signals. Also, a minimum of one "1" bit per eight bit time slot is thereby guaranteed.

Abstract: Heat generated from electronic equipment packed densely on a circuit board is transferred to conductive partition plates located adjacent to and on opposite sides of the circuit board. Heat is then transferred from the partition plates to conductive shelves located above and below the partition plates and then to a conductive rear wall of a cabinet. Heat is then transferred through the rear wall to a plurality of external fins and then to the atmosphere by radiation and convection. Alternatively, the circuit boards are housed in sealed enclosures. A clamp, fastened to the rear wall of the cabinet, is used for securing the sealed enclosure and for transferring the heat from the electronic equipment to the rear wall.

Abstract: An electret transducer for producing a directional response, electret foil (92) and a backplate (94) with the actual air gap thickness therebetween varying in accordance with a predetermined relationship. The sensitivity of the electret transducer varies inversely as the actual air gap thickness. In one embodiment the actual air gap thickness is realized by a plurality of posts (90) having heights varying according to the aforesaid relationship. In another embodiment, the actual air gap thickness is realized by varying the thickness of the aforesaid backplate.

Abstract: An electret transducer for producting a highly directional response characteristic comprises a backplate (18) and, superimposed thereon, an electrostatically charged electret foil (10). The electrostatic charge varies according to a predetermined relationship. The sensitivity of the electret transducer, at any point thereon, is directly proportional to the electrostatic charge on the electret foil at that point.

Abstract: An electret transducer comprises an electrostatically charged electret foil (10) superimposed directly over a selectively metalized rough surface (16) of a backplate (18). Selective metalization is realized by depositing a thin metal layer (20), the contour of which is defined by a predetermined relationship, over the rough surface (16). The sensitivity of the electret transducer at any point thereon is directly proportional to the width of the metal layer on the backplate. The response characteristic of the electret transducer comprises a main lobe and a plurality of sidelobes below a preselected threshold.