Reltec Corporation

Arnold M Ladd

Richard T Kaczmarek

Louis Suffi

A network interface device (37, 37a) for use with a communication system. The communication system includes a plurality of interconnect elements (39) coupled to incoming and outgoing lines (41, 47). The network interface device is selectively and individually coupled to selected ones of said interconnect elements to test incoming lines of the communication system. The network interface device includes a first connector (34) for coupling a shared test device (53) thereto, or the shared test device itself. A second connector (38) is coupled to the first connector, for example, by a cable (36) and is used for selectively and individually coupling to a selected one of the plurality of interconnect elements. The network interface device is normally disconnected from the communication circuit and is a passive element until it is connected to the interconnect element. Use of the second connector will interrupt circuitry between contacts (43, 45) in the selected interconnect element. A pair of binding posts (57, 59) may be coupled to the first connector.

Network interface device for line testing

A protector unit for use in retrofitting connector blocks, such as a 300-type connector block or a C-50 frame includes a housing; a back-up, fail-safe assembly for providing a connection to ground; and a positive temperature coefficient limiter ('PTCR') for temporarily preventing the passage of current through the protector unit when an over-current condition is detected and for allowing the passage of current through the protector unit when the over-current condition is no longer detected. The back-up, fail-safe assembly permanently prevents the passage of current through the protector unit when a sustained over-current condition is detected.

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Des Plaines, IL, United States of America

Arnold M Ladd