Abstract: A base station for interconnecting via a wireless full duplex communication path, a plurality of stationary intercom unit stations with at least one portable transceiver unit. A page channel interface arrangement coupled to the stationary units and the base station interconnects the stationary units and the portable units with a common paging arrangement to enable all the users of the system to be alerted about messages to be transmitted.

Abstract: A method and apparatus for detecting objects disposed in close proximity to a conductive loop, includes the use of a sensitivity selection circuit to compensate for loop sensitivity to metal and other conditions, and a microprocessor circuit for helping to prevent false detections or undesired interruptions of valid detection due to changes in environmental conditions.

Abstract: A universally adaptable battery charger connector which couples electrically a battery charger outlet to pairs of terminals of different types and kinds of rechargeable battery devices. The universal adaptable battery charger includes an attachment arrangement for engaging releasably one of the pairs of battery device terminals. The attachment arrangement includes a pair of electrodes coupled electrically to a battery charger outlet for helping to supply electrical current to the battery device terminals. The universal connector also includes a securing device for mounting removably on the battery device to be charged. Each one of the electrodes includes a resilient contact for pressing resiliently into engagement with the terminals to maintain an electrical and mechanical contact between the securing device and the battery device terminals.

Abstract: The drive-up station full duplex communication system is adapted for use in a building having a drive-up vehicle lane at the outside thereof, and having a customer speaker post at the lane for enabling a customer to communicate verbally with personnel within the building to enter into a transaction. A transceiver used by personnel to communicate with a customer via a base station, is disposed within the building includes a device for attenuating a received audio signal when an outgoing audio signal is being transmitted. A customer speaker post at the drive-up station includes a device for similarly attenuating the incoming audio signal when an audio signal is being transmitted to the transceiver unit disposed within the building. Full duplex communication is achieved while substantially decreasing or eliminating unwanted feedback interference at both units.

Abstract: A light frequency communications system and method of using the system is disclosed. The system includes a base station and a plurality of remote units wherein the base station and all the remote units communicate in a full duplex mode utilizing a single light wave carrier. Multiplexing between the units is accomplished by modulating an audio signal on at least one subcarrier frequency.

Abstract: A stationary optical antenna forming a part of a full duplex optical communication system, includes optical emitter and receptor devices having peak power axes, and a mounting arrangement for positioning the devices at an elevated location within a room with their axes directed downwardly at a given angle to a horizontal plane, based upon the height of the devices above the floor, thereby enabling remote portable transceivers to be able to communicate therewith within the same room. Baffles help prevent interference between the emitters and receptors, and a compensation circuit is employed to enable the optical communication to take place, even in bright light conditions.

Abstract: A fastener includes a base plate for permitting the portable equipment to be supported from the apparel of a user. An apparel clip is mounted pivotally to the base plate for moving between open and closed position for securing removably the apparel of the user to the portable equipment. In one form of the invention, the apparel clip is biased by a spring to a closed position in order to permit the portable equipment to be attached to the waistband of the user. In another form of the invention, the apparel clip is locked to the portable equipment so the wearing apparel captured by the apparel clip is incapable of being released from the clip except by the direct action of the user.

Abstract: A method and apparatus for establishing communication paths includes a portable transceiver carried or worn by a company representative, for communicating in a wireless mode of operation with a stationary base station, thereby enabling the representative to move freely about for performing multiple tasks. A plurality of customer stations outside of the company building are connected electrically to the base station, which includes a switching arrangement to select an individual one of the customer stations for connection to a base station transceiver. The portable transceiver includes a single input device in the form of a push button paging switch for each customer station. The single device causes a customer station to be selected, a communication link to be established and terminated, and controls both the customer and the representative audible communications.

Abstract: A wireless communication system is adapted to be used as an intercom system in a multiple customer station configuration. A customer service representative portable transceiver communicates wirelessly with a stationary base station to enable the representative to move freely about, and thus be able to perform other tasks. The base station is connected electrically to a group of substantially similar physically spaced apart remote customer drive up stations. Each of the remote stations includes a call initiating device for enabling a customer at a drive up station to request communications with the representative. The base station includes a signal generator, which responds to a call initiating device requesting a communication link. A transmitter responds to the generator to send an attention attracting signal to the representative's transceiver, so that the representative can cause the establishment of an audio communication link to a selected customer station.

Abstract: A battery charging system which prevents false switching from a fast charge mode to a trickle charge mode due to low frequency voltage aberration signals. The battery charging system includes a battery voltage analyzer and a plurality of battery charging and conditioning units for charging different types and kinds of nickel cadmium batteries. Firmware in the microprocessor rejects low frequency aberrations permitting a desired voltage signal to be produced which is indicative of the actual battery potential for charge switching purposes.

Abstract: A communication system includes a filter device for passing only a desired carrier frequency, and a circuit for splitting the passed carrier frequency into a pair of signals. A circuit for feeding back one of the signals to the filter device for causing an oscillation to occur at the desired carrier frequency for direct broadcast purposes.

Abstract: A wireless optical short-range communication system adapted for use as an intercom system. The system can be used in fast food restaurants and similar commercial institutions. The communication system includes a base station to interconnect via optical communication a group of substantially similar physically spaced-apart, remote units. Each one of the remote units and the base units includes an optical emitter to transmit an optical message-carrying beam to the base station, and an optical receptor to receive an optical message-carrying beam from the base station. The base station includes a receptor for receiving the optical beam transmitted by the optical emitters of all of the remote units, and an optical emitter to relay the received optical beam to the optical receptors of all the remote units.