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.