Cat 5, ( cat5e ) short for Category 5, is the current
preferred industry standard for network and telephone
wiring. Cat 5 is an unshielded twisted pair type cable
exclusively designed for high signal integrity. The cable
consists of four pairs of 24-guage twisted copper pairs
terminating in an RJ-45 jack. If a wire is certified as
Category 5 and not just twisted pair wire, then it will
have "Cat 5" printed on the shielding.
The actual Cat 5 standard describes specific electrical
properties of the wire, but Cat 5 is most widely known as
being rated for its Ethernet capability of 100 Mbit/s.
Category 5 cable comes with three twists per inch of each
twisted pair of 24 gauge copper wires within the cable.
The twisting of the cable helps to decrease electrical
interference and crosstalk. Each wire in a Cat 5 cable is
insulated with a plastic (FEP) which has low dispersion.
The importance of this insulation is that the dielectric
constant of the plastic does not depend mainly on
frequency.
Because most people already have a broadband (high
speed) internet connection already, VoIP voice over IP
phones can turn this connection into a way to place free
phone calls. The practical upshot of this is that by using
some of the free VoIP software that is available to make
Internet phone calls, you are bypassing the phone company
(and its charges) entirely.
VoIP is a revolutionary technology that has the potential
to completely rework the world's phone systems. You may
well have heard or even be using the skype system. This
uses your computer as the intelligence that converts your
speech into voip packets. It means that if you buy a cheap
(£10-£20) USB handset you can “call” via the computer
someone else anywhere in the world that has similar
equipment. This is great news for families and friends
that end up all over the country or world, but what if you
need to speak to them when they are away from their
computers ie business users.