Abstract: A web break detector which utilizes sonic signals to detect the occurrence of a break in a moving web in web handling machinery. A separate sonic transmitter and receiver transducer are utilized to provide improved speed of detection, and enhanced reliability. The dual transducer detector can also be placed closer to the web to enhance reliability and efficiency. Multiplexing is utilized to permit multiple detectors to be operated with reduced complexity and minimal mutual interference. The transmitting transducer is triggered to emit a sonic burst for a predetermined time period and at a predetermined rate. The receiving transducer is activated for a predetermined time duration beginning a predetermined delay period after the sonic burst is triggered and generates a detection signal in response to receiving the reflected burst. The absence of the detection signal causes generation of a control signal to stop the web handling machinery.

Abstract: An electronic tour guide system is disclosed which provides messages about exhibits in a museum or the like to visitors carrying portable receivers. Audio sources which generate various messages are provided at a central location which are multiplexed and digitized and applied to one or more cables which extend to the covered areas. Receiver-transmitters are located along the cables and are adapted to decode one of the messages and transmit the same via infrared energy into a well defined area adjacent the exhibit, enabling a visitor having a receiver to receive the infrared radiated signal information and hear the message.

Abstract: A dictating machine control unit includes apparatus connected to a telephone transmission line and adapted to respond to signals received over the telephone line for controlling the operating functions of a dictating machine, such signals being produced by operation of a telephone instrument, which may be either the coded tone type or the dial type. The apparatus responds to the detection of a ringing signal received over the transmission line for generating a guard tone and recording the same on a record medium to identify the beginning of a recording and to serve as a buffer, providing security for previously recorded messages. The functions of "record," "play back," "review," "stop," "correction mark," "end of letter mark," and "cell attendant" are controlled in response to touch tone signals or dial pulse signals generated by operation of the telephone instrument.

Abstract: A circuit for controlling the application of one or more audio signals to a plurality of channels incorporates a series of voltage controlled amplifiers for interconnecting an individual signal source with different channels at different times, and a control apparatus for selectively energizing the voltage controlled amplifiers in a selected sequence and at selected times so that the signal can be applied successively to the channels in accordance with the selected pattern or program. A second plurality of voltage controlled amplifiers are provided to accomplish the same function with respect to a second signal source, and the program for the energization of the second group of voltage controlled amplifiers may be the same or different from the first program.