Abstract: A ringing control system which receives ring inputs, detects the type of input, translates the input into digital PCM format for transmission across a digital line such as a multiple channel span line. At the remote end of the line, the PCM signals are reconverted into relay operating data for emitting output signals of types corresponding to the input ringing signals. The ringing signals may be divided ring for either the tip lead or the ring lead and also may be frequency selective, superimposed or coded ringing. The arrangement is designed for use in a digital multiplexer or subscriber loop multiplexer.

Abstract: Mounting structure for a bay of racks of electrical equipment, such as telephone switching apparatus which extends vertically between a support floor to almost the height of a cable runway extending horizontally between racks of the bay. Each rack includes at least one subrack comprised of sidewalls with horizontal separators joining the sidewalls. The separators mount switching modules in a slide-in relationship. One sidewall of a subrack is hinged to the cable runway to enable the subrack to be tilted away from the normal vertical position allowing access to a paired subrack and to cables connected to the tilted subrack.

Abstract: A telephone instrument circuit including electronic components for functions such as amplifying incoming and outgoing speech signals. When the electronic transducers of each electronic instruments have to operate in parallel with a carbon microphone in another instrument, problems are likely to arise. To deal with the problem, a voltage regulator is used which includes two essentially series coupled comparator-amplifiers, the first of which is driven by the circuit's supply voltage. The second amplifier has its own reference voltage and its output varies the reference voltage V.sub.R for the first amplifier, whose output is connected to the line whose voltage is being regulated. Above a preset line current, the I-V characteristic of the circuit is almost flat while below the preset threshold it is fairly steep to enable satisfactory parallel operation.

Abstract: To limit the line current dissipation in a telephone system it is considered desirable, especially in electronic systems, for the line current feed to be constant current. In the present arrangement the constant current supplied to the line is made adjustable in accordance with line conditions, especially the voltage between the line wires. A high impedance monitor is connected across the line to monitor the voltage between the two wires and to produce therefrom a reference voltage which is applied to the constant current generator so as to cause it to generate a current for line feed whose value is determined by the line voltage.

Abstract: A telecommunications system for both PABX and key systems use.The system is assembled in modules capable of physical and electrical interconnection and expansion. The system has a control apparatus housed in one modular sectional unit. The stations of the system are grouped with the control for each group being housed within a sectional unit. The units are adapted for physical mounting to one another and each unit is electrically connected into the system by two flat conductor cables jumpered to the adjacent unit. This modularity is made possible by each unit having internal bus structure for the bidirectional flow of information in the module, the intermodular connection acting as the bus between groups and the central control. Further, each group has a data memory for storing information directed into or out of modular unit on a random basis for reading out that information when the destination module is ready to receive that information.

Abstract: A radio receiver employing paired signal paths with frequency shift keying. In each signal path pair in which demodulated signals in quadrature are produced, the outputs of the limiting amplifiers are connected to two pairs of flip-flops so that the phase changes in the amplifier outputs are indicated. The outputs of the flip-flops are selectively summed in two gates to drive the inputs of a further flip-flop the output of which is the decoded output signal.

Abstract: The present invention is directed to a multiple line telephone instrument operative over a pair of data conductors and a pair of speech conductors using time division principles. The data pair transmits line condition signaling and control using an asynchronous sixteen bit binary code while the speech and dialing information is sent over the speech pair of conductors in standard analog format for translation to PCM code within the system (not shown herein). Line condition signaling between an instrument and its group logic circuit or group processor is in parallel over the data pair. Incoming line condition signaling information is used to generate an audible signal and to illuminate a selected lamp representing the desired line. Outgoing line condition signaling is encoded in diphase code using a square wave of a second frequency to represent a binary zero. The outgoing encoding ensures that only one or the other binary signal is sent and to ensure that the signals are sent in diphase mode.

Abstract: A keyboard assembly for a multiple button array in which each push button is individually pivotal about a resilient hinge which is deformable throughout its length or a "living hinge" mounting to a support structure. The engagement of the hinge mounting to a push button is located adjacent the end of the button most remote from the connection of the hinge to its support structure. The hinge mechanism for each button comprises plastic straps extends along both sides of the button to the connection to the button. The hinge axis for the straps is spaced a distance from the near side of the button to produce a button movement of a translatory rather than pivotal movement. The button array disclosed is suitable for use as a telephone push button dialer.

Abstract: A mechanism using a stepping motor as the prime mover for a bar code printing head or hammer mounted on the end of a pivotal lever. Where the output code (such as the postal code used in the U.S.) requires a full bar as one binary indication and a half bar the other binary indication, two motors each with its own printing head are used. The heads are spaced apart longitudinally relative to an object to be printed. A full bar is made up of two half bars, thus, both motors must be energized at separated time intervals to cause both heads to strike in a single transverse alignment to print a full bar. The lever supporting the printing head is constructed to position its center of percussion essentially in alignment with the printing hammer to minimize wear on the motor shaft.

Abstract: An impedance network used for ring trip or loopsupervision purposes in a telecommunications system. The network employs a multi-port impedance bridge with one set of opposed terminals (first port) coupled to the line loop being supervised and the opposed terminals (second port) coupled to an AC ringing source. A third port is coupled to intermediate points in the impedance of opposite bridge legs. The third port leads to a low pass filter network and ultimately to a DC detection circuit. The third port is also coupled through impedances to the AC source to receive an attenuated AC component signal to cancel any stray AC components entering the detection circuit.

Abstract: A display device for alphanumeric characters using a sixteen segment configuration for each character, eight segments in an outer ring and eight segments in an inner configuration. The segments are joined in an eight-by-two matrix which is multiplexed, there being two time intervals for each character. The display medium may be liquid crystal or any other known dual plane medium such as colloidal suspension. In one plane, the inner eight segments are multiplexed into one group, while a second group multiple extends to the external eight segments. In the other plane, each outer segment is connected in series with an inner segment to form eight segment pairs. To display a desired character, selected pairs in one plane are energized with either the inner or outer multiple during one time interval to illuminate all segments common to the selected pairs and the selected group. During a second time interval, other selected pairs are energized with the other group. Successive characters are driven sequentially.

Abstract: A time division multiplex communication system comprised of a plurality of modules, each module being equipped with a space division concentrator and a processor. The modules are interconnected by a control bus and by a plurality of speech busses, the number of speech busses being equal to the maximum number of modules. All busses are connected to each equipped module. The control bus is commonly connected to all modules and this bus is, in turn, controlled by a control circuit. In the control circuit, there is a flip-flop for each module for enabling a scanner in the control circuit to set the address of a module seeking use of the control bus. The processor in the module seeking service recognizes its address and transmits its call processing data on the control bus. Each speech bus is comprised of eight wires for parallel PCM bit transmission with time slot interchanging.

Abstract: A four-transistor bridge amplifier is adapted for use as a bidirectional speech amplifier between a telephone line and an electronic telephone subscriber's instrument. The amplifier is powered from the line and includes two-transistor sections, one or other of which functions dependent on line polarity. The output of the amplifier to the subscriber instrument is taken across a resistor connected between the transistors such that the output always has the same relative polarity whatever the line polarity.

Abstract: A chair mechanism having a seat portion, a back rest and arm rests. The arm rests are individually supported on arms mounted on the seat support member. The seat back is mounted to a telescoping seat bearing column with the seat enabling joint movement. The back rest is also movable independently relative to the seat. The connection of the arm rests to the support arms and the support arms to the seat body is through the use of universal joints allowing movement in all directions. The seat bearing column rests on a circular base plate with roller sets about its periphery. With the multiple, wide angle range of adjustments which may be easily performed, the chair mechanism provides comfortable, multi-use support for its occupant.

Abstract: The mechanism uses a drive block having mounting lugs on both transverse sides of the block for mounting in slots on opposed sides of a C-shaped bracket. The slots in the bracket are T-shaped, the body of the T accepting the mounting lugs for passage to the circular T head opening. By rotating the block 90.degree., the lugs rest in the circular opening and are held in place. Each lug has a necked down section passing through the slotted opening of the brackets. Each lug has an enlarged head extending outwardly of the bracket sides to prevent the bracket sides from spreading in response to shock forces acting on the seat track. The block has a central threaded opening to accept a lead screw for driving the seat track responsive to rotation of the lead screw. The bracket is secured to the seat track and the drive block is inserted into the bracket, rotated to position and mated with the lead screw.

Abstract: A system for monitoring the liquid level in containers such as boilers and tanks. An electrode inserted into the container completes a path through the liquid when the liquid is at or above a predetermined level. When the liquid falls below the level, the path is opened. If the open path persists uninterruptedly for a timed period, an output device such as a relay is energized (or deenergized, if desired) to signal the low fluid level. The circuit path is powered at a low AC level from an AC source which also powers the output device. The low level AC in the circuit path to the liquid minimizes electrolytic and other problems within the container. The low level AC periodically resets a timing device within a direct current monitoring circuit before the expiration of the timed period, as long as the circuit path through the liquid remains closed. The output device is an optical coupling device isolating the output device from the timing device and from the low level AC path.

Abstract: A relay for use in automotive vehicles. The construction of the relay allows the assembly of all the contacts and relay armature through a contact chamber open at one end. The chamber is formed by a unitary coil winding support and contact chamber closed on all sides but the one open end. The open side is adapted to be covered by the mounting of the relay to a printed circuit board with the contact spring terminals adapted to extend from the relay structure to extend through the board.

Abstract: A radio receiver for frequency modulated (FM) tones. Received signals are split and one split portion of the signal is phase shifted relative to the other and mixed with a local oscillator. The signal as received clocks a flip-flop. The phase shifted signal is fed to the switching input of the flip-flop. The input signal having been modulated with an FM tone which oscillates about the frequency of the local oscillator, the output of the flip-flop is a digital waveform the frequency of which is the same as that of the modulating tone. This digital waveform is applied to a band pass filter accepting the fundamental frequency of the digital wave form from the flip-flop for passage to a detector.

Abstract: A readily assembled transducer assembly. The assembly includes a cup-shaped housing for the transducer magnetic structure. The housing has sized slots for receiving the pole piece tips and nesting members for positioning the coil bobbins, the pole pieces and permanent magnet bar within the housing. The cup is placed on a plate of magnetic material so that the pole tips are attracted to the plate and held firmly in place. With the pole tips held, a potting compound may be introduced into the cup cavity. As the compound is hardening, terminals and a cap cover may be applied. When the compound has set, the assembly is removed and is ready for use.