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.