Abstract: Disclosed is a system for rapid, wireless communication of electrically-generated and detected, serial digital data signals via a plurality of infrared (or other compatible wireless medium) transceivers. Signals are communicated without electrical connection among computers, fax machines, computer peripheral equipment, or may be employed within self-contained communication, control data-acquisition, and/or display systems. The system operates at predetermined maximum data rates and sub-multiples thereof. The disclosed transceivers can be joined with additional circuits, to form an arrangement that operates as a wireless modem. In each arrangement, light is continuously modulated at either of two precise multiples of the predetermined maximum data rate, and is synchronized to transmitted-data transitions. Upon receipt of light-signals thus produced, the system's receiving transceiver synchronizes received-data electrical output signals to the received modulated light signals.

Abstract: A self-contained theft and vandalism deterrent system for equipment security includes sensors (12) for detecting conditions to which an alarm (24, 26, 28, 50) is responsive. The analog signals from the sensors (12) are serially delivered by a multiplexer circuit (16) when they are then directed to a network (20) for conversion to digital signals. The digital signals are delivered to a micro processor (22) where the signals are evaluated to determine if an alarm condition exists. The sensing means (12) include sound and vibration detectors for monitoring the ambient envelope. The micro processor (22) includes built in reprogramming and comparator circuits for varying the level at which a given condition will trigger an alarm response.

Abstract: A circuit for making existing automatic number identification (ANI) equipment in a telephone central office compatible with multifrequency tone telephone using tone-to-pulse converters. In a typical ANI system, the telephone of one party on a two-party line includes an identification circuit, such as a connection to ground, while the other telephone does not include such a connection. When one party initiates a call, the tone-to-pulse converter interrupts the direct line pair connection between the telephone and the central office, in order to convert the multifrequency tones generated by the telephone into corresponding pulses recognizable by the central office. During this period, a voltage comparator in the preferred embodiment of the identification forwarding circuit serves to detect the voltage condition of the line pair portion connected to the one telephone, which condition varies depending on the presence or absence of the connection to ground in the telephone.