Harris Corporation

Leonard E Curtin

Richard W Faith

Ben A Pierce

Steven R Coffelt

Aaron Chan

James D Eckman

Chuck Muir

A telephone line test and display circuit for enabling a craftsperson to automatically monitor a plurality of communication aspects of a telephone line without impacting any communications that may be taking place over the telephone line being monitored includes a communication capability detection and indicator unit through which the craftsperson may observe the DC operational state (busy/idle, battery polarity, talk battery present) condition of the line by observing a pair of light emitting diodes. The light emitting diodes are color-coded in accordance with operational status conditions being monitored and are illuminated in either a steady state or flashing condition, depending upon the DC state of the line. Also contained with the test and display circuit is a frequency discriminator/display unit, having a set of light emitting diodes separate from those employed for monitoring the DC operational status of the telephone line. The frequency discriminator/indicator unit monitors the line for the presence of communication signals and selectively illuminates an individual one of a set of light emitting diodes, each of which is associated with a prescribed frequency band of signals.

Telephone line test and display circuit

A direct access test unit for testing subscriber lines is located in the central office and is accessable from a remote location through a standard ground start line circuit. The field technician involved in a troubleshooting problem dials the number of the ground start line circuit followed by a security code to gain access to the test unit which then returns dial tone. Dialing the number of a subscriber line to be tested provides for access to that line via the test unit and a test trunk connected thereto. Various tests may be performed on the subscriber line thus accessed by dialing a selected digit to identify the test. The test unit provides voice messages to the field technician to instruct in the use of the test unit and explain the available test operations and how they may be initiated.

Direct access test unit for central office

A party line interface for permitting the connection of a standard telephone to a telephone central office which rings selected subscribers by applying a DC ringing potential of a selected polarity to a selected one of the tip and ring lines of the party line and a ringing tone is disclosed. The interface includes a signal path having two lines with each line having an input terminal and an output terminal. The input terminals are respectively adapted to be connected to the ring and tip lines of the party line. A programmable switching means is coupled to the signal path for selectively applying the ringing signal received by the party line interface to the output terminals for application to the ringing mechanism within the standard telephone as a function of the polarity of the DC component and ground reference applied to the input terminals by the telephone company central office. The ringing signal is applied to the standard telephone by the interface only when a chosen one of the two possible DC polarities provided by the party line central office is applied to a chosen one of the pair of lines of the signal path.

Interface for connecting standard telephones to party lines

A party line interface for permitting connection of a standard two-wire telephone designed for non-party line use to a party line system which rings subscribers by party line ringing signals of different frequencies. The interface includes circuitry for generating a ring command signal in response to the receipt of a party line ringing signal of a specified single frequency chosen from the group of possible ringing frequencies of the party line. The party line ringing frequency to which the circuitry for generating the ring command signal responds is programmable to permit selection of the particular party line ringing frequency to which the ring command signal will be generated in response thereto. Circuitry is provided for producing a ringing signal of a standard frequency designed to ring a standard telephone in response to the ring command signal.

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Houston, TX, United States of America

Leonard E Curtin