Abstract: A key telephone system comprised of a key service unit connected to a plurality of local sets via four-wire conductors for providing full duplex signal communication between the key service unit and sets. Signals are carried by a first pair of each of the conductors for unidirectional transmission of signals from each set to the key service unit, and the remaining pair of conductors carries signals transmitted by the key service unit for reception by one or more of the sets. Four-to-two wire signal conversion and line impedance balancing is effected by one or more trunk circuits of the key service unit in the event one or more of the local sets are connected via the key service unit for communication between the sets and the outside telephone lines.

Abstract: New methods and apparatus are disclosed which allow measurement of the presence of oil and water in geological formations using a new physical effect called the Acoustic Paramagnetic Logging Effect (APLE). The presence of petroleum in formation causes a slight increase in the earth's magnetic field in the vicinity of the reservoir. This is the phenomena of paramagnetism. Application of an acoustic source to a geological formation at the Larmor frequency of the nucleons present causes the paramagnetism of the formation to disappear. This results in a decrease in the earth3 s magnetic field in the vicinity of the oil bearing formation. Repetitively frequency sweeping the acoustic source through the Larmor frequency of the nucleons present (approx. 2 kHz) causes an amplitude modulation of the earth's magnetic field which is a consequence of the APLE.

Abstract: An apparatus is described having the capability to selectively alert subscribers in a telephone party line system where different subscriber parties are alerted using different ringing configurations. Subscribers are identified as being a member of a party by the connection pattern used to interface the apparatus to the telephone party line. The apparatus comprises means for detecting whether a ringer signal received from the telephone line is meant to alert a given subscriber party, and means for coupling the ringer signal to subscriber alerting equipment when an appropriate ringer signal is detected.

Abstract: An electronic apparatus includes a plurality of selectively actuable selection devices for causing the apparatus to perform a plurality of distinct operations. A first actuation of a selection device establishes a first condition to cause the apparatus to generate an externally detectable identification such as by voice synthesis of the selected operation, and a second actuation of the selection device establishes a second condition to cause the apparatus to perform the selected operation and identify the operation on a display. In a preferred embodiment, the selection devices are each a push button actuable from a rest position to a first depressed position to establish the first condition by actuating a first switch, and thereafter actuable from the first depressed position to a second depressed position to establish the second condition by actuating a second switch.

Abstract: In a building cable system, a building cable has a portion for carrying electronic data signals for networked digital computers and a second portion for carrying electronic telephonic signals for telephone instruments. The system includes a relay rack with a data cross connect panel connected to the data signal carrying portion of the building cable for carrying data signals. A wire terminal panel is mounted on the relay rack. The wire terminal panel includes a pair of supports fixed to the relay rack. A pivot pin is mounted on each of the supports. A telephone block bulkhead is pivotally mounted on the pivot pins to pivot relative to the supports and the relay rack. A bulkhead lock releasably connects the telephone block bulkhead to one of the supports to hold the telephone block bulkhead in a selected position. The telephone block bulkhead includes a wall.