Abstract: A hold and dial monitor accessory is provided for use with a conventional telephone instrument connected across a subscriber service pair extending from a central office. The hold and dial monitor accessory is bridge connected across the telephone service pair and includes a manually actuable and releasable line seize switching circuit for controlling a line hold circuit connectable across a communications loop through the central office. The line seize switching circuit has an internally established time constant for automatic line release whenever a telephone handset is taken off-hook, and an audio amplifier and loudspeaking circuit is provided for amplifying audio information present on the telephone service pair during the interval when the line hold circuit is holding the communications loop.

Abstract: Full duplex local intercom circuit arrangements are provided for telephone station instruments within a local network. Each instrument includes an FM receiver and an FM transmitter. If two subscriber telephone paths are provided, switches are also provided to reverse the connection of the paths of e.g. the calling party station relative to called party stations. The switches may be manual or automatic. If a single subscriber telephone path is provided, alternative carrier frequencies are selectively generated, with the calling party receive and transmit frequencies being reversed for the called party frequencies, either automatically, or manually. In all arrangements, the establishment of a normal telephone circuit through the central office over the subscriber line(s) has no effect on intercom communications, and vice versa.

Abstract: A detection circuit is provided for indicating whether a telephone line is in use or is available or is on hold. The simplified circuit can be incorporated within a telephone instrument so that no external circuitry is required.

Abstract: A golfer's aid is provided in the form of a translucent sheet having two transparent crosses thereon wherein the center of the crosses corresponds with the separation of a user's eyes, and a pair of vertical and horizontal slots, respectively, above and at the outer sides of said crosses, said sheet being pivotally supported by extension arms well in front of the user's eyes.

Abstract: A line powered loudspeaker telephone is provided with a lightweight headset and microphone as well as a loudspeaker and second microphone. A first switch is employed to go from the loudspeaker to the headphone and their respective microphones while a second switch is used as a listen-talk switch, preventing acoustical feedback.

Abstract: The bandwidth of human speech signals, 125 to 3000 Hz, is reduced to approximately 125 to 1500 Hz by folding or shifting the high-frequency consonant-band portion, 1000 to 3000 Hz, into the low-frequency vowel-band portion, 125 to 1000 Hz. After transmission, the reduced speech signal is expanded to reconstruct an approximation of the original speech signal. One embodiment features folding (modulator carrier frequency is 3000 Hz) and modulator feedthrough. Another embodiment features shifting (carrier is 1800 Hz) and no modulator feedthrough. Both embodiments boost lower vowel frequencies prior to modulation, and use no switching circuitry.

Abstract: A repeater is provided for a smoke alarm or similar alarm device which picks up the sound from the alarm device and transmits a coded radio signal to a receiver at a remote location. This receiver includes an integrator set for some convenient time interval to prevent false triggering. In accordance with a preferred embodiment of the invention, the receiver may incorporate a location indicator and be used with a plurality of transmitters.