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Cables of Paired Twisted Wires

Annealed copper wires are used in cables. Each wire is insulated with a paper tape, or with a layer of "paper" applied to the wires in the form of paper pulp.2 The wires are twisted together into pairs. In some cables used for toll service, two pairs are twisted together into a four-wire arrangement called a quad1 which is used as a phantom group.

The cables are composed of wires of several different A.W.G. sizes. The smallest wire sizes used are 28 gauge.3 Usually, however, the smallest wire size used is 26 gauge. With these it is possible to place 4242 wires (2121 talking pairs) in a cable sheath having an outside diameter of 2f inches. In the past, the cable sheaths were of lead-antimony alloy. This sheath excludes moisture and protects the wires mechanically. Cables with plastic sheaths(1) are also used.


(1) See "Alpeth Cable Sheath" by R. P. Ashbaugh, Bell Lab. Record, November, 1948, Vol. 26, No. 11..

Home Cables and Wave Guides Cables of Paired Twisted Wires

Last Update: 2011-05-30