Coaxial (coax) cables work well to transmit electronic signals
(data or anything else). First, let’s look at the construction.
Coax cables are composed of a center wire that is surrounded by an
insulator (or dielectric) and then the whole of the inside is
surrounded by a shield (like wire braid). There is (usually) a
vinyl or rubberized jacket over the whole thing. The central wire
and the shield act similar to two wires in a “twisted pair”
configuration. In a basic or simple model of conduction by two
wires, a voltage is applied to the ends of the two wires. Current
will then flow (if it can) “out” from the source on one wire, and
”back” toward that source on the other. At another instant of time,
current flow in the wires will be reversed. It doesn’t matter if
the wires are a flat pair, like in a lamp cord, a twisted pair,
like in a pair for connecting a phone, or the two conductors (the
center conductor and the shield) as in a coax cable. (Certainly the
characteristics are different in all types of conductors. Keep it
simple here….) The coax cable has some, um, quirks. But the
curious reader can find out more by using the link to the article
posted by our friends at Wikipedia, where knowledge is free.