Any cable design experts out there? A question.

[3moons]

I have questions on a type of cable found in my workbench junk box. On the surface it looks like a typical microphone cable found anywhere. There are two center leads. One with red insulation. One with clear. Each of these colors is then covered with black insulation. Then there are copper spiral strands as the shield. It is a very flexible cable. Nothing too surprising except when examined closely. I used a 10 power loupe. The copper strands of the center leads AND the copper strands of the shield are both really spiral strands of copper wrapped around centers of an insulated material. I've seen a design similar many years ago in a Telco cable. This one is a discontinued cable sold under Radio Shack's Archer brand. Can anyone explain the design? Why of the design? And where I might find something similar to experiment with? Thanks. jim...