Abstract: A self-correcting intercom system with circuitry to detect faults within the circuitry and phone lines and reset the system to a pre-fault condition on the occurrence of a fault. The intercom system has an alarm system with a line control unit and a timer to reset the intercom system to a standby condition. A set up control unit includes all of the codes and signals to reset the other components of the intercom system upon activation of the set up control by the timer or the line control unit. A timer activates the set up control unit when a user initiates a call from an entrance vestibule panel to an apartment unit and no connection has been made within a certain time period. A line control unit activates the set up control when a connection is made, but a line fault such as a short circuit occurs disrupts normal communication. The system consumes electrical power only when needed.

Abstract: In a single-line telephone, there are a plurality of extension telephone sets connected by a telephone line and each extension telephone set is connected to a communication controlling apparatus. The communication controlling apparatus includes an alternating current coupler and a power supply thus allowing two extension telephone sets to communicate with each other without being disturbed by a busy tone.

Abstract: A method of establishing a telephone communication link from a calling line to one of plural peripheral devices associated with a single telephone number in a central office telephone switching system or PBX is comprised of storing in a memory a first table of directory numbers and equipment identifiers associated with each directory number, storing in a memory a second table of references to physical peripheral devices associated with each equipment identifier, receiving a request for service to a particular directory number, accessing the first table using the particular directory number and obtaining references to all equipment identifiers associated therewith, accessing the second table using the particular equipment identifiers associated with the particular directory number and identifying the particular physical peripheral devices associated with the particular identifiers, ringing all of the particular physical peripheral devices, detecting one of the particular physical devices going off-hook, ceasin

Abstract: A system of telephone answering devices includes a master telephone answering device (MTAD) and at least one (and often a plurality) of extension telephone answering devices (ETADs). If a telephone call is answered by someone, others nearby may be paged through the ETADs from any telephone. The ETADs can be temporarily disarmed so that they do not respond to tone codes that might otherwise activate them. When activated, the ETADs transmit back to the caller noticeably different ringback signals to indicate that the activated ETAD is responding to the caller's commands. For telephone utilities offering a distinctive ring service, the ETADs may respond to distinctive rings corresponding to the ETADs by usurping the function of and disabling the MTAD and by subsequently answering the telephone call.

Abstract: The device and method of the present invention characterizes a telephone call by identifying a code, comparing the code to a predetermined access/ID code and generating a signal in response to the code. The device provides called party identification, calling party identification, and telephone number identification.

Abstract: A data dial system having at least one matrix switch, one or more user terminals, one or more Touch-Tone push button telephones, and at least one processor. The matrix switch can switch the user terminals between various inputs and outputs. The Touch-Tone push button telephones, each of which has a dual-tone-multiple-frequency keypad, generates signals which can actuate the processor. The processor controls the operation of the matrix switch, for switching signals between signal sources and signal destinations by establishing connections and by performing disconnections of the various inputs and outputs of the matrix switch.

Abstract: A page party system for use in industrial environments, having a plurality of stations joined by a page line and by a single party line for providing multiple full-duplex conference calls over the single party line. Multiple full-duplex conferencing is achieved by combining single sideband suppressed carrier amplitude modulation and frequency division multiplexing.

Abstract: A signal distribution and communication arrangement controls the broadcast of different types of signals through speakers located in various zones. The system includes a telephone interfaced with a door speaker controller to allow communication between the telephone and a door speaker. A page may be broadcast over the speakers and subsequently muted to allow private communication when the page is answered. Also included is a doorbell interface circuit that responds to a doorbell source. The doorbell source may be activated by any one of a plurality of doorbell switches.

Abstract: A virtual private line key telephone system is provided. The system includes a console including a plurality of line keys each associated with a party that can be reached via a switched trunk line. A look-up table means associates the line keys with the telephone numbers of the associated parties. A communication path is established from the console to one of the trunk lines. Signals are sent to the central office via the selected trunk line corresponding to the telephone number in the look-up table means associated with a line key that is actuated to place a calls. The telephone number of incoming calls are determined and compared with telephone numbers in the look-up table. Thereafter the line keys which are associated with the incoming calls are determined. The incoming call is coupled to the console when a line key associated with the incoming caller is actuated.

Abstract: A page party system for use in industrial environments, having a plurality of stations joined by a page line and by a single party line for providing multiple full-duplex conference calls over the single party line. Multiple full-duplex conferencing is achieved by combining single sideband suppressed carrier amplitude modulation and frequency division multiplexing.

Abstract: An internal telephone intercom system including means for connecting to a dedicated telephone communication line, a plurality of telephone sets connected to the line and adapted for telephone communications with locations external to said dedicated line, an audio receiving means at each telephone set for receiving audio signals from a microphone within said telephone set, a radio frequency generator means for generating a carrier frequency and amplitude modulated responsive to said audio signals with said modulated signal being multiplexed on said dedicated line, an audio expander for receiving a modulated signal from the radio frequency generator means and producing an audio signal responsive to audio sounds at a speaker.

Abstract: Two-wire television interphone system is arranged to discriminate by a line voltage discriminator incorporated in a master device a line voltage variation due to a calling operation on the side of a branch device, to actuate a voltage controller in the branch device to shift the system from standby state to operation state, and to drive a call signal generator in the branch device for actuation of a call signal receiver in the master device. The system is thus made to have a power supply circuit energized for a power supply to the system only when required for effecting the calling operation, talking between the both devices, and so on.

Abstract: A field telephone system having a widely dispersed set of telephone lines including a page line pair and a party line pair, audio processing equipment including telephone handsets, handset amplifiers, receiver amplifiers and paging speaker amplifiers is designed to have improved voice transmission by provision of a narrow band FM carrier system. The FM carrier system includes a device for generating a carrier frequency signal, a modulator for modulating the carrier frequency with an audio signal derived from one of the handsets at a transmitting station and circuitry for transmitting the modulated signal over a line pair to a receiving station. The receiving station includes circuitry responsive to the transmitted signal and the carrier frequency signal for extracting the audio component of the transmitted signal and for processing the extracted audio signal and for providing the processed audio signal to a handset at the receiving station.

Abstract: On board functions are performed in an aircraft with the aid of a central control computer connected to a plurality of input and output devices including data terminals for passengers and flight attendants, through a data bus system and through decoder/encoder units linking the data terminals to the data bus system for providing an operation with digital signals. Thus, digital signals are transmitted back and forth between the central control computer and the data terminals in such a way that computations initiated on a data terminal are performed by the central control computer and so that the computation results and any other information are displayed on a display field forming part of the data terminals, one of which is provided at each passenger seat. Modified terminals are provided at various other locations within the aircraft cabin for use by a flight attendant.

Abstract: Aircraft communications apparatus includes a permanent communications system, a temporary communications system and an interface coupler connecting the permanent and temporary communications systems. The coupler consists of a plurality of opto-isolator circuits each of which couples signals between one of the permanent communications and one of the temporary communications circuits thereby reducing the transmission of noise between the circuits. The coupler further includes a plurality of normally-closed bypass relays each connected in parallel with one of the opto-isolator circuits which are controlled by manually-operated switches to bypass the opto-isolator circuits in the event of a malfunction.