A known ribbon cable having optical fibers and electrical conductors is disclosed in U.S. Pat. No. 4,678,264. The ribbon cable includes optical fibers and electrical conductors, spaced apart side to side within a surrounding, flexible jacket, and each optical fiber and each conductor is contained within a corresponding sleeve of the jacket. An advantage of ribbon cable, as disclosed in U.S. Pat. No. 3,775,552, is that the optical fibers and electrical conductors are in a common plane, and are readily accessible for stripping off and insulative jacket of the cable, and for termination of the optical fibers and the conductors by corresponding optical couplings and corresponding electrical connections.
One disadvantage of ribbon cable is its lack of capacity for flexure in the common plane of the conductors and optical fibers. Ribbon cable is unsuitable for use in an environment that requires flexure of the cable in many different planes.
Another type of cable that is more suitable for flexure, contains multiple optical fibers in a bundle, wherein the optical fibers are not in a common plane and are packed closely together side to side in the bundle to reduce the number of interstitial spaces along the length of the bundle. For example, DE 3328-948 discloses a cable of this construction. The cable is capable of flexure in more planes of flexure than is a ribbon cable, but lacks the advantages of a ribbon cable wherein parallel optical fibers are in a common plane.
Another disadvantage of ribbon cable resides in its construction that lacks a structural feature to distinguish one lateral side of the cable from the other lateral side.