At&t Bell Laboratories

American Telephone and Telegraph Company, At&t Technologies, Inc.

Timothy S Dougherty

Valerie Jeanne Kuck

Raffaele A Sabia

Stanley Kaufman

Kent B Connole

Edward Dennis Nelson

Karen D Dye

Maureen Gillen Chan

Robert E Streich

Leonard D Loan, Deceased

An insulated conductor (20) for use in a communication cable which includes a filling material (30) includes a copper conductor (25) and a composite insulation system (27) comprising two concentric layers of insulation. An inner foam layer (28) of the insulation comprises a cellular plastic material (28) which includes a stabilizer system. An outer layer (29) of the insulation is referred to as a skin and comprises a stabilized solid plastic material. The stabilizer system in each of the cellular and solid layers includes a bifunctional portion that functions as an antioxidant and as a metal deactivator and that has a relatively high resistance to extraction. The level of the bifunctional portion of the stabilizer in the cellular material is substantially greater than that in the skin inasmuch as it has been found that the level of the stabilizer cellular layer contiguous to the copper wire determines the oxidation performance level of the composite insulation.

Metallic transmission medium disposed in stabilized plastic insulation

Cordage (17) which may be used for any of the commonly marketed lengths of etractile cords comprises an array of a plurality of conductors (11--11) each insulated with a suitable plastic material. The array of conductors is enclosed in inner and outer jackets (52, 54). The inner jacket comprises a polyvinyl chloride (PVC) plastic material, for example, and has a thickness of about 0.015 inch. Covering the inner jacket is an outer jacket comprising a polyvinyl chloride plastic material having a thickness of about 0.005 inch and having a colorant constituent. The PVC composition of the inner jacket is such that it is a less expensive composition than that of the outer jacket. Enclosing the outer jacket is a layer (56) which comprises a top coating material. The top coating material provides the cordage with enhanced retractibility and prevents discoloration as well as plasticizer migration from the outer jacket.

Universal cordage for transmitting communications signals

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Phoenix, AZ, United States of America

Timothy S Dougherty