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.