Abstract: A circuit for detecting a true seizure condition of a trunk calling bridge relay employs a timer which is incremented every 40 milliseconds as long as a continuous trunk off-hook representative signal is supplied thereto for approximately 300 milliseconds. For momentary changes in the condition of the trunk CB relay the timer will be incremented and decremented so as to effectively filter out momentary trunk calling bridge seizure changes.

Abstract: A digital interface especially useful for isolating a speedily responsive circuit from the effects of transients at its input such as may be caused, for example, by contact bounce in a relay. The circuit includes a monostable multivibrator connected to be set in response to changes of alternately opposite polarity of the input signal and having a characteristic period equal to a predetermined fraction of the normal minimum interval between intended changes of the input signal. The output of the multivibrator is used to drive a flip-flop at the end of the characteristic period to produce the desired output signal. Thus, the circuit is non-responsive to relatively rapid alternations of the input signal immediately following a change of its condition, yet responds reliably when the input signal changes state and remains stable in its new state for a time exceeding the characteristic period of the multivibrator.

Abstract: The subject of the disclosure is low-pass filter apparatus for use in filtering out noise in a signal channel for propagating PAM signals. A sample and hold circuit which operates in synchronism with the presence of PAM pulses is provided as the input section. The output of the sample and hold circuit is applied to a four-pole, low-pass, RC active filter network. An adjustment is made to the active filter network such that the filter network's low frequency complex pole pair is changed to provide compensation for an undesired roll-off of band pass in the intended in-band region due to the frequency response characteristics of the sample and hold circuit. The resultant apparatus provides a significant reduction in active filter gain required for a given PAM duty cycle. It also provides increased noise rejection capability in the out-of-band region of operation.

Abstract: A scanner arrangement for scanning both line circuits and incoming trunk circuits simultaneously in groups with priority being given to the scanning of incoming trunk circuits. A sequencing means provides for individual scanning of line circuits of respective groups in which a possible request for service exists and the priority for trunk circuits is effected by inhibiting this sequencing and immediately scanning a selected group of trunk circuits.

Abstract: A telephone transmission bridge including a transformer having primary and secondary windings, connected between first and second input leads and first and second output leads, respectively, has a varistor connected in series with a relatively small number of tertiary windings wound around the transformer core. The tertiary windings and varistor present a high AC impedance to signals transmitted via the input and output leads, thereby permitting AC signals to be transmitted freely via the primary and secondary windings. When transient DC signals are impressed on the input and output leads the tertiary windings and varistor exhibit a low DC impedance, the varistor conducts effectively short circuiting the primary or secondary windings to which the transient signals are transmitted and the transient signals are prevented from being transmitted through the transmission bridge.

Abstract: An arrangement is disclosed for providing trunk consultation in an electronic private automatic branch exchange which is built around a space divided solid state matrix. The trunk consultation arrangement is enabled by a hookswitch flash from a consulting PABX station connected to an established incoming or outgoing trunk call and directs the trunk junctor associated with that call to place the connected trunk on hold. While the connected trunk junctor is in a held status, the consulting PABX station is forwarded to a local junctor where the consulted trunk party is dialed. A connection between the consulting PABX station and the consulted trunk party is then established via a second trunk junctor. Further circuitry is provided in the trunk consultation arrangement to establish a three-way consultation between the consulting PABX station, the consulted trunk party, and the held trunk party.

Abstract: A method of service code conversion and a service code conversion control circuit are disclosed for translating a dialed service access code in an abbreviated form into the directory number of a line circuit. A class-of-service indication assigned to a calling line circuit and a dialed abbreviated service access code are steered from a common register to a first translation circuit normally providing outgoing routing information for trunk marking. Instead of providing outgoing routing information, the first translation circuit or translator is strapped to recognize the class-of-service indicator and abbreviated dialed access code to enable a service code conversion control circuit. The service code conversion control directs the first translator to perform a conversion of the access code to a type of call indicator and a directory number, both of which are returned to the common register.

Abstract: A call queue release control circuit for automatic toll switchboards is disclosed. The call queue release control circuit is supervised by a plurality of multi-position switches that are set in accordance with decisions made at a chief operator position as to the number of different types of calls to be released in an allocation chain. Individual numbers of calls to be released are loaded through guarded inputs into separate presettable counter circuits associated with the type of call to be released. A sequencing circuit addresses the plurality of counter circuits in succession to form the allocation chain. As a particular counter circuit is addressed, the sequencing circuit provides an enabling signal to a call queue control circuit for releasing the type of call associated therewith and receives from the call queue control circuit a confirmation signal for every call released.

Abstract: An improved loudspeaking telephone system including voice switching is disclosed. The system is bistably voice controlled by inversely regulating the impedances of variolossers in the transmit and receive channels, respectively. Hysteresis is added to the bistable control by the summation of receive and transmit signals across a plurality of unequal impedances that form part of an input control means. Circuitry forming the input control means also includes transmit noise guard circuit means useful in discriminating between ambient noise signals and syllabic speech signals. Further, a novel receive noise guard circuit means is used to discriminate between syllabic speech signals and high level noise transmissions from another station. The outputs of both the transmit and the receive noise guard circuit means are summed with the transmit and receive signals across unequal impedances to prevent seizure of the bistable control by ambient noise and to improve the receive channel sensitivity.

Abstract: A loudspeaking telephone system including voice switching is disclosed. The system is bistably voice controlled by inversely regulating the impedances of variolossers in the transmit and receive channels respectively. Further provision is made for switching additional impedance in parallel with each variolosser control to provide for a loud and a soft receiving mode. Hysteresis is added to the bistable control by the summation of receive and transmit signals across a plurality of unequal impedances that form part of a novel input control means. Circuitry forming the input control means also includes noise guard means useful in discriminating between ambient noise signals and syllabic speech signals. The noise guard circuit discriminates between noise signals and speech signals by producing an output whose amplitude is substantially related to ambient noise conditions while the noise guard circuit generally is not responsive to rapidly fluctuating voice signals.

Abstract: A local transfer arrangement for an electronic private automatic branch exchange having a space divided rectangular solidstate switching matrix is disclosed. The local transfer arrangement is provided with means for sensing a local transfer indication from either a calling station or a called station connected by a local junctor. The transfer indication causes the system to forward the transferring station to a second local junctor and hold the first local junctor. A transferee station is then signaled via the second local junctor of the impending local transfer by the transferring station. Thereafter, an automatic forwarding of the transferee station to the first local junctor is initiated by an on-hook condition of the transferring station to complete the operation. Additional features of the arrangement provide for a return to the original call and release of the connected junctors responsive to an on-hook or hookflash condition of the transferring station.

Abstract: A universal answer arrangement for a PABX in which incoming trunk calls are automatically connected, when all operator positions are busy or unattended and equipped for universal answer service, to a pre-designated line circuit or, at night, to one or more selected operator position circuits. In response to the connection to an associated operator loop circuit, a programmable automatic dialing circuit transmits a programmable predetermined number to a local register which effects a switch-through from the incoming trunk to the designated line circuit. The operator loop circuit monitors the connection and releases from the call when the called line goes off hook. Advantageously, the night answer arrangement includes a PABX group hunting circuit which permits the incoming call to be connected to a second line circuit if the first line circuit is busy or to a tie line trunk to another PABX having a night attendant if all line circuits in the hunting group are busy or disabled.

Abstract: Apparatus and method for the uniform dipensing of a conductive epoxy binder in hybrid microcircuit applications. A method is disclosed of uniformly pressurizing a conductive epoxy binder through a small orifice until a droplet of fixed volume forms, setting a predetermined gap size between a contact pad and the droplet in order to control the shape and size of the epoxy droplet left on the pad as the droplet touches it, and then releasing the pressure while reciprocating the dispenser from the pad. Also, apparatus, including a cylindrical limiting means attached to the dispenser tip, is disclosed for ensuring the gap size is constant. Other embodiments of the limiting means provide for the use of a relieved section which assists in preventing contamination and for adjusting means operable to vary the gap size.

Abstract: In an electronic private automatic branch exchange telephone system, busy test is carried out by way of a two step process. Initially, a junctor memory is scanned and the called number is compared with each ING and ED number contained in memory. At the completion of the scan and comparison a check of the calling bridge relay of the called number is made. Associated with the busy test arrangement are camp-on and call-waiting features which may also be carried out during the test.

Abstract: A method and apparatus are disclosed for providing automatic toll ticketing in a common control telephone system. The method includes sequences which provide automatic ticketing for station-to-station sent paid local or tributary terminations with automatic or operator number identification. The apparatus includes an adapter circuit connected to the common control for directing the transfer of toll information from common registers to a toll buffer. An automatic recorder is controlled by the toll buffer and a plurality of recording trunks to receive charge information and provide a permanent record of the toll charges for the common control system.

Abstract: A tie trunk control arrangement is disclosed for providing tie trunk connections in an electronic private automatic branch exchange which is built around a space divided solid state matrix. Each tie trunk has an associated tie trunk junctor dedicated thereto which may be connected to local stations by the PABX system in a manner similar to other trunk junctors. For incoming tie trunk connections an attendant extension or station attendant extension is used for providing connections to other PABX stations and trunk circuits. Common circuitry used for trunk transfer and trunk consultation may be used by the station attendant to extend the tie trunks to the PABX stations and the outgoing trunk junctors. Further circuitry is provided by the tie trunk control arrangement to allow a tie trunk and a central office trunk to be tandemed in the system or to allow two tie trunks to remain tandemed in the system without attendant supervision.

Abstract: An electronic private automatic branch exchange is built around a space divided solid state matrix. One side of the solid matrix provides line appearances which are connected to line circuits, tone receivers, senders and operator loops. The other coordinate side of the matrix provides junctor appearances for connection to an attendant junctor, local junctors and trunk junctors. The solid state switching matrix is a single stage matrix providing direct connection between line appearances and junctor appearances by the closing of a single crosspoint, and connection between lines within the system is effected simply by the interconnection of a pair of crosspoints associated with the respective lines and a selected junctor, thereby providing a greatly decreased switching for establishing a connection through the matrix. The control necessary for effecting such connections is provided with much simpler common control equipment than is utilized in a conventional multistage switching network.

Abstract: An automatic number identification system in a tributary office having simultaneous dual operation for high traffic capacity. A pair of identifier units applying identification signals via the sleeve wire associated with the calling stations to a common matrix or directory number network.

Abstract: An interface circuit is disclosed for ground starting central office trunks connected via a station carrier system to a plurality of PBX subscriber terminals. The interface circuit extends ground start signals between central office sensing means and subscriber terminal control means over the high frequency transmission cable of a multiple-channel station carrier system. Associated with each of the plurality of multiple-channel units that interface central office terminal trunks to the carrier system are ground start sensing means multiply connected to ground start common circuitry. The ground start common circuit interprets signals from the ground start sensing means as to which of the voice frequency connecting pairs indicates a signal ground and subsequently forwards this information in the form of modulated intelligence on a discrete carrier over the high frequency transmission highway.

Abstract: A circuit is disclosed for providing trunk transfer in an electronic private automatic branch exchange which is built around a space divided solid state matrix. The trunk transfer circuit is enabled by a hookswitch flash from a transferring PABX station connected to an established incoming or outgoing trunk call and directs the trunk junctor associated with that call to place the connected trunk on hold. While the connected trunk junctor is in a held status, the transferring PABX station is forwarded to a local junctor by the trunk transfer circuit and a connection is established from the local junctor to a transferee PABX station. The trunk transfer circuit then completes the transfer by establishing a connection between the held trunk and the transferee PABX station via the held trunk junctor.