|
|
| Technical
Training > Cable introduction |
| |
| |
BNC
Coaxial Vs. RCA Vs .Cat5
| |
Maximun
Lenght |
| Cat5 (Active Video Balun) |
10,000' |
| Cat5 |
1,000' |
| Coaxial |
500' |
| RCA |
25' |
|
BNC Connector 
RCA Connectors  |
When selecting cables for video, either RCA, BNC coaxial
cable or Category 5 twisted pair cable can be used. BNC cables
generally have lower losses than RCA, are more rugged, and are
most commonly constructed using coaxial cable, such as the one
which runs in your home to connect with the cable company. This
type of cable is referred to as RG-58 and RG-59. RG-58 cable is
lighter and more flexible that RG-59, but has a little more loss
at higher frequencies. The BNC connectors are usually molded onto
the cable end. Standard pre-made cable lengths are 3', 6', 10',
25', 50',100', 150' and in bulk come in rolls of 500' or 1,000'.
Although RG-58/-59 cable is great stuff, it's relatively heavy
and may be awkward. With the advent of video baluns (a small lipstick
size device) you can now run video and power over a Category 5
cable. The Category 5 cable also known as Cat5 carries four pairs
of wires allowing for more runs on a single cable and being much
lighter is easier to work with. While distances beyond 500' becomes
a video signal problem for BNC, Cat5 can comfortably extend out
to 1,000' and with active video baluns that distance can be increased
to 10,000'. Much debate is made as to whether BNC or Cat5 produces
a better signal.
There are many grades of RCA cables available, some intended
for audio, some for video, and some for both. RCA cables are
usually thinner and not as rugged as BNC cables. For cable lengths
under 20 to 25 feet, most RCA cables provide acceptable results
for both audio and video but you will rarely if ever see professionals
use RCA. At lengths of as little as 30 feet, RCA cable can start
to show a measurable loss at the higher frequencies, depending
on the quality of the cable. RCA cables usually have molded
connectors at the cable ends and the connectors themselves may
come with tin plating (standard) or with gold. The gold looks
nice, but is really not necessary for a good, reliable connection.
|
| |
Coaxial
Cable
A type of wire that consists of a center wire surrounded
by insulation and then a grounded shield of braided wire. The
shield minimizes electrical and radio frequency interference.
Coaxial cabling is the primary type of cabling used by the cable
television industry and is also widely used for computer networks
and CCTV. Although more expensive than standard telephone wire,
it is much less susceptible to interference and can carry much
more data. |
| |
Plenum
Cable
A type of cable that is run in the plenum spaces of buildings.
In building construction, the plenum (pronounced PLEH-nuhm) is
the space that is used for air circulation in heating and air
conditioning systems, typically between the structural ceiling
and the suspended ceiling or under a raised floor. The plenum
space is typically used to house the communication cables for
the buildings CCTV, computer and telephone network(s). However,
use of plenum areas for cable storage poses a serious hazard in
the event of a fire as once the fire reaches the plenum space
there are few barriers to contain the smoke and flames. Plenum
cable is coated with a fire-retardant coating (usually Teflon)
so that in case of a fire it does not give off toxic gasses and
smoke as it burns. Twisted-pair and coaxial versions of cable
are made in plenum versions. |
| |
|
RJ45 Connector vs. RJ11 Connector

|
Cat-5
Cable
A network cabling that consists of four twisted pairs of copper
wire terminated by RJ45 connectors. Cat-5 cabling supports frequencies
up to 100 MHz and speeds up to 1000 Mbps. It can be used for 1000Base-T,
100Base-T, and 10Base-T networking.
Computers hooked up to LAN s are connected using Cat-5 cables,
so if you're on a LAN, most likely the cable running out of the
back of your PC is Category 5.
RJ45 Connector
Short for Registered Jack-45, an eight-wire connector used commonly
to connect computers onto a local-area networks (LAN), especially
Ethernets. RJ-45 connectors look similar to a telephone line connector
( RJ-11 connector), but they are somewhat wider.
RJ-11 Connector
Short for Registered Jack-11, a four- or six-wire connector used
primarily to connect telephone equipment in the United States.
RJ-11 connectors are also used to connect dial-up modems to the
internet using your telephone line.
|
|