Abstract: A method for substituting one memory module for another, faulty, memory module comprises designating and marking a memory module as the substitute module, which, upon detection of a fault in the other memory module, is inhibited from responding to its own address when called, and responds to the address of the faulty module whenever the latter is called.

Abstract: An optical fibre has a core and a plurality of rings surrounding the core. In one arrangement the core and subsequent alternate rings are light transmitting, while the intermediate rings are of cladding material. In an alternative arrangement the core and alternate rings are of cladding material and intermediate rings are light transmitting. The light transmitting rings can be of varying refractive index or of constant refractive index.

Abstract: A method of producing an insulated electrical conductor, in which a wire conductor is coated with an inner layer of heat resistant material and covered with electrostatically deposited powdered polymeric material which is fused by heat to form an outer layer of insulation. An insulated electrical conductor produced by this method comprises a core carrying an inner coating of heat resistant material and an outer coating of fused polymeric material.

Abstract: Apparatus for treating portions of the arms or legs of a human body with heat and moisture by means of a moisture-resistant heating pad retained in a cylindrical configuration by means of a fabric enclosure having means to receive the heating pad and retain it in its circular configuration in close proximity to the body member being treated. A suitable moisture source is provided in the form of a pad positioned in the enclosing material.

Abstract: A limiter circuit for the extracted timing signal in high speed digital repeaters is disclosed. The conventional emitter-coupled transistor pair limiter is modified by applying to the base of the output transistor the decoupled, attenuated, and delayed signal at the collector of the input transistor. The delay is such that the compensating signal at the base is out-of-phase with respect to the input signal by approximately -5/2.pi.. Experimental determination of delay and attenuation yields optimal phase and amplitude responses which are a significant improvement over those of the conventional limiter.

Abstract: A TDM PCM communication system includes a plurality of user terminals, a switching network and a CPU for controlling the establishment of transmission paths between the user terminals and the switching network for the transfer of information between predetermined ones of the user terminals. An incoming path carries information bits from the user terminals to the switching network and an outgoing path carries information bits from the switching network to the user terminals. The switching network includes means for transferring single information bits each residing in a time slot period from the incoming path to the outgoing path. The transferring means includes an exchange means for effecting a bilateral exchange of information bits in fixed pairs of time slot periods, whereby paths for information bit transmission are periodically provided between ones of the user terminals, as determined by the CPU.

Abstract: In a telephone unit having a plurality of line selection pushbuttons, normally released on replacement of the handset, an additional release switch is provided with associated circuitry, whereby when a speaker unit or "hands free" unit is attached, pushbuttons can be actuated by a solenoid, even though the handset is not removed. The normal hold button is altered to a momentary button, and the solenoid releases all depressed pushbuttons. An additional circuit is provided for preventing actuation of the solenoid and release of an actuated pushbutton on cessation of a call when an answering service module is connected.

Abstract: An electric blanket control circuit is provided which includes an overheat protection circuit to detect an overheat condition as well as a fail-safe testing circuit to assure that the electrical components in said overheat protection circuit are properly functioning. A simulation circuit is provided to electrically simulate an overheat condition in the blanket. An on-off switch is provided which will consecutively activate the overheat simulation circuit and then the fail-safe testing circuit so that said circuits are activated each time the electric blanket is turned off by the user.

Abstract: An analog signal processor in which the voltage is sensed across a plurality of charge storage elements to derive an output signal. With this arrangement, the effects of signal interaction encountered in charge sensing are eliminated. The processor can be readily implemented using MOS (metal-oxide-silicon) technology whereby the charge is manipulated by electronic data and stored at the surface of the semiconductor substrate. It is particularly adapted for use as a programmable cross-correlator or a transversal filter.

Abstract: In an electronic telephone a speech network for connecting a transmitter and receiver to a line powered telephone line which utilizes a bridge configuration that is so arranged that the network will function on very low d-c line voltages, thereby enabling the set to be connected in multi-party applications with a conventional hybrid transformer set on long loop applications.

Abstract: A push button switch has a spring contact plate and a circuit board in superposed position. The spring contact plate has one or more switch positions, each switch position comprising a prestressed domed portion surrounded by a flat sheet portion. The domed portion includes a central portion and radial webs connecting the central portion to the flat sheet portion. Spring contacts extend radially from the central portion, each contact between a pair of webs. The domed portion is prestressed to assume a stable position offset upwards from a plane coincident with the flat sheet portion, and the webs each have an upwardly bent portion at the junction with the flat sheet portion. A push button acts on the central portion and pressure on the push button causes the central portion to snap through the plane of the flat sheet portion, with the spring contacts contacting contact areas on the circuit board. Release of the push button enables the domed portion to snap back to the stable position.

Abstract: A multiple frequency signalling receiver translates combinations of tone signals received from a telephone set to derive binary two out of eight coded signalling. Received signals are directed by a filter to high and low band translator circuits. Each translator circuit includes a circuit for deriving a threshold signal from the received signal and a threshold signal controlled limiter for limiting the received signal. The threshold signals are cross coupled between the limiter in each translator to prevent response to signals in the high and low bands being substantially unbalanced in amplitude. Digital counting and decoding circuits in each translator circuit detect predetermined frequencies of signals from the limiting circuits. Upon occurrence of a consistent detection by both the translator circuits lasting for at least about 40 milliseconds, the appropriate two out of eight code is gated to the output terminals of the multifrequency receiver.

Abstract: An interface circuit adapted to selectively input serial and parallel PCM coded words and to selectively output serial and parallel PCM coded words is connected to a memory means. The memory means has a storage capacity for at least 2.sup.n memory words, each one having an address corresponding to a respective one of the PCM coded words appearing at the interface circuit and each one representing X db of signal level variation relative to its corresponding coded word. The output of the memory means is connected back to the parallel input of the interface circuit. A control means provides timing and control signals for loading the interface circuit with one of the coded words and for causing the memory means to be addressed at the location defined by the coded word. The control means includes means for circulating the coded word through the memory means a predetermined number of times M.

Abstract: A circuit for suppressing noise pulses generated by the transfer of a charged telephone line from one supervisory circuit to another is provided. A capacitor is first connected to the telephone line and is charged to the voltage level appearing across the telephone line at the one supervisory circuit. The telephone line is then transferred from the one supervisory circuit to the other supervisory circuit and the capacitor is disconnected from across the line.

Abstract: A connecting block in which a support member has a large number of terminal clips extending through the member, for connection of wires to both ends, the support member pivotally mounted in a housing so that one or other side of the support member, and related ends of terminal clips, can be selectively presented for wiring. A hinged cover attached to the support member can be utilized to retain the support member in one selected position, the support member normally positioned in the other position, as by gravity.