Abstract: A circuit which prepares a conductive path between a ringing voltage generator and a telephone subscriber loop circuit prior to the application of ringing voltage to the conductive path. Photo coupled switching and monitoring circuits are used to coordinate application of ringing voltage with operation of a ring relay which completes the circuit path between the ringing voltage generator and the loop circuit.

Abstract: A routinable clock circuit for use in an automatic identification of outward dialing (AIOD) system. The clock circuit consists of asynchronous receive and transmit portions connected and utilized in such a manner as to permit a central processing unit to routine both portions in conjunction with one another to determine whether a fault condition exists. Should such a fault condition exist, the circuitry can be used to determine in which portion the fault lies and to further localize the fault to a functional area within the particular portion of the clock circuit. The clock circuit normally functions to drive logic circuitry for transmitting and receiving data consisting of information associated with calls initiated at a remotely located PABX.

Abstract: A thick film resistor which fuses at low continuous current yet withstands high voltage pulses. The resistor design comprises a series of smaller thick film resistors disposed on a ceramic substrate, each having laser trimmed kerfs strategically located to control current flow and prevent voltage arcing across the kerfs.

Abstract: A power control circuit which supplies all of the power requirements of a telephone subscriber's loop circuit in a digital telephone switching system. A central processing unit generates digital power supply selection and control signals which are decoded and stored by the power control circuit. These signals are then supplied to a selected programmable power supply for selected time durations.

Abstract: Rectangularly shaped snapstrates are separated into substrates along kerfs that are parallel to edges thereof by belt and roller flexure forces produced by two belts that are caused to be contiguous over the suspended length of the upper belt by a pressure roller forcing the two belts together at an intermediate point between roller supports for the belts. This produces oppositely facing curvatures in the belts at spaced apart transverse lines thereon which flex snapstrates in opposite directions with a flexure force which is sufficient to separate snapstrates on the lower belt with kerfs facing in the right direction and which is not sufficient to separate snapstrates there with kerfs facing in the wrong direction. In an alternate embodiment, the peripheries of rollers are tapered in vertical sections for separating snapstrates along kerfs oriented at right angles. In a further embodiment, only a single belt with a pressure roller pressing down on it is employed to separate snapstrates.

Abstract: A retainer for accommodating and routing flat ribbon cable comprising two flat panels hinged at one end and arranged to latch together, wherein flat ribbon cable can be angularly routed in any desired direction and retained in position between the latched panels.

Abstract: A calling device usable in telephone subscribers' instruments to selectively close a set of contacts upon the depression of one of a plurality of upwardly biased pushbuttons. The device is adapted to be assembled modularly and includes an integrated switching module arranged as an unitary assembly. A plurality of one piece spring and contact members within the switching module serve to restore each pushbutton and provide a single "make" contact with an included contact strip whenever an individual pushbutton is depressed. Formed wiper contact ends of each spring and contact member and contact strip, electrically connect to a circuit board which is disposed to engage a rear face of the switching module. The front face accepts a faceplate and pushbutton assembly which is keyed to the switching module and is easily removed and replaced without disassembling the entire calling device.

Abstract: Digital Carrier Trunks connected via a supervisory decoding and multiplexing logic to an electronic digital PABX. The circuit is arranged to receive or transmit the supervisory signal in either the "Ground Start", E&M modes or a combination of both in either the D2 or D3 signalling format over a T1 carrier span without converting to the analog signal form.

Abstract: A circuit which detects the presence and absence of a telephone subscriber loop, before and after ringing current is applied to the loop. Coils functioning as magnetic field generating devices and a Hall effect device are used to perform the detection function. Inclusion of a capacitive shunt network limits the responsiveness of the Hall effect device during ringing, permitting use of the device on lines to which multiple ringers are connected.

Abstract: A data synchronization circuit for use in an automatic identification of outward dialing system (AIOD). The present invention automatically synchronizes streams of binary data sent as lengthy messages between a private automatic branch exchange (PABX) and a telephone switching center. The binary information transmitted to the switching center consists of the calling subscriber's identity within the PABX and the identity of the trunk circuit connecting the PABX to switching center. This information is transmitted in two-out-of-five code. Synchronization is provided by controlling the output of an included clock in response to received binary state changes.

Abstract: A call for service and continuity sensor circuit for use in conjunction with a trunk circuit of a digital PABX telephone system interfacing with a central office via ground start signalling providing for detection of a call for service signal to the PABX by the central office. This circuit also provides the means to effect an open circuit for both signalling and transmission conditions in order to prevent excess loading of the trunk circuit during these conditions. This circuit provides a precise and stable threshold detection level necessary for accurate sensing of the trunk circuit conditions mentioned above despite parasitic leakage current, induced longitudinal power line voltages, and earth potentials sometimes existing on the line connecting the PABX to the central office.

Abstract: A tool and method for installing a flexible tube between two or more glass encapsulated reed switches of a multi-capsule reed relay switching assembly. The tool is formed from a steel wire in a wedge shaped structure, adapted to compress when the tubing is fitted over it, exerting pressure against the inside wall of the tubing and narrowing the tubing into an egg-shaped configuration. This allows the insertion of the tubing between the reed capsules with a minimum of interference.

Abstract: A telephone hookswitch actuator and handset support assembly arranged to allow a telephone instrument to be used as either a desk or wall unit. The actuator is constructed of two independently pivoting members, a first hookswitch actuator member controlling the "on-hook" and "off-hook" switching and a second alternatively positionable support member. When the telephone instrument is intended to be used as a desk unit a retaining device manipulated from the exterior of the telephone is adjusted out of contact with the support member allowing the support member and actuator to act in unison. When used as a wall unit the retaining device is adjusted into contact with the support member which then retains the member outwardly extended allowing a cavity on the handset to accept the support member, supporting the handset.

Abstract: A tool and method for installing a flexible tube between two or more glass encapsulated reed switches of a multi-capsule reed relay switching assembly. The tool includes a rectangular horizontally oriented insertion member with a billhook raised at one end. The rectangular insertion member is arranged to narrow the tubing into a slightly egg-shaped configuration when the tubing is fitted over it. The billhook is adapted to partially penetrate an inside wall of the tubing allowing the tool to essentially drag the tubing into place. During installation the tubing collapses against the insertion member reducing the amount of initial interference between the tubing and the glass reed capsules.

Abstract: A circuit which overrides the initial rate circuit included in a coin telephone, to allow the central office to perform coin collect and refund operations independent of whether or not the initial rate has been deposited. This circuit operates in response to coin battery applied by the central office to operate a rate relay which connects the included coin relay to the central office.