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Most computers are networked with unshielded twisted pair cable (UTP). An older technique uses coaxial cable. UTP allows faster transmission speeds than coaxial.
This was used before twisted pair cable, it is RG-58 coaxial cable with a 95% braided shield. Each node was daisy chained together, and when one was disconnected, the entire network went down. Today some hubs are chained together with RG-58 cable. It is called ThinLAN Ethernet. The maximum distance end to end is 200 meters (about 667 feet).
This was very difficult to use as the cable was the thickness of your big toe. It is called ThickLAN and is used for the backbone of data networks. With the advent of twisted pair cable, it is rarely seen. The maximum distance end to end is 500 meters.
10 Base T is a point to point topology and uses CATEGORY 3 unshielded twisted pair cable. It is capable of speeds up to 10 megabit. The most common connector type is an eight wire RJ-45 telephone type connector. The plug must be rated at 10 megabit. Only four of the eight wires are actually used, pins 1, 2, 3 & 6. See below wiring diagram.
Maximum distance from PC to hub is 100 meters (about 328 feet).
100 Base T is similar to 10 Base T, but is capable of transmission speeds up to 100 megabit. It is called CATEGORY 5 and also uses UTP. The difference is that the cable has more twists per inch of cable, thus handling higher speeds. The connector is also an RJ-45 plug, but uses all eight wires, per the IEEE 802.3 standard. The plug must be rated at 100 megabit.
Maximum distance from PC to hub is 100 meters (about 328 feet).
Allows increased performance characteristics with bandwidth up to 350 MHz. Usually gives a 6dB gain improvement in pair to pair and a better NEXT (near end cross talk). Supports the ATM standard.
Future networking applications, such as 622 Mbps ATM and 1000Base-T will require increased bandwidth and utilize full duplex operation over all four pairs.
Category 5 (and cable) used for running in a building is 24 gauge solid unshielded twisted pair (UTP) cable with either a PVC jacket or a plenum rated jacket.
Shielded twisted pair (STP) category 5 cable is used mainly for extending the DEMARK on T1 circuits and where machinery may disrupt the signal of data transmission. One type of STP cable is called D-shield, where each pair is individually shielded. Regular STP cable has only an overall foil shielding.
PVC stands for Poly Vinyl Chloride, which is the insulation used around the copper wires. When it burns, it emits a poisonous gas. Plenum Rated, which is a TEFLON (copyright Dupont) or FEP coating burns at a much higher temperature and is not as toxic.
When should I use PVC and when should I use Plenum Rated?
Well it depends. PVC cable is about 1/2 to 1/3 the price of Plenum Rated cable. Plenum rated cables is used in air plenum ceilings where the return air is forced through the ceiling, rather than being ducted through air conditioning tubes. You should check with the Building and Safety Department of your City. Different cities have different regulations. In general, Plenum Rated cable must be used in an air plenum ceiling.
4 Pair cable
Most all CATEGORY 5 (and 3) wire conforms to the AT&T color code. Each twisted cable pair has a primary color (called tip) and a secondary color (call ring). Tip and ring are telephone terms that we will use. The primary color for a four pair CATEGORY 5 cable is ALWAYS white and the secondary colors are BLUE, ORANGE, GREEN and BROWN.
A full listing of the AT&T 25 pair color code can be found in the Telephone Technical Support Page (see top).
So the 4 pair color code is as follows:
| Pair # | Primary (tip) | Secondary (ring) |
| 1 | White/Blue | Blue/White |
| 2 | White/Orange | Orange/White |
| 3 | White/Green | Green/White |
| 4 | White/Brown | Brown/White |
NOTE: When we say "White/Blue", we mean a white colored wire with a ring of blue around it. When we say "Orange/White", we mean an orange colored wire with a ring of white around it.
UTP cable is usually four pair cable. Each pair is two wires twisted around each other, hence UTP. Wires are identified by colors. Each cable pair has two colors, one is primary and one secondary.
For example, the 1st wire of the 1st pair is all White (primary color) with a ring of Blue (secondary color). The 2nd wire of the 1st pair is all Blue (secondary color) with a ring of White (primary color). The primary wire is called TIP and the secondary wire is called RING (telephone terminology).
When wires are punched down to a patch panel (or 110 block) below is the color code.
POSITION PAIR COLOR CODE
Below are examples of 66 blocks and 110 blocks. If you are using a 66 block, make sure that it is certified for CATEGORY 5 cable (for 100 Base T).
110 block 66 block
This is the front of an RJ-45 wall plate. The tab is down and pin #1 is on the left. It is wired to the T568B standard with Orange/White being the first wire.
The 568B wiring is used in almost 90% of installations. The pin numbers refer to a RJ-45 telephone type connector. Pin #1 is the one on the left when you hold the tab down with the wire facing you, as you would plug it in. Pin #2 is the next one on the right and lastly, pin #8 is the one all the way to the right.
PIN # COLOR SCREW TYPE COLOR
NOTE: This
is an RJ-45 wall plate (front view), T568B.
The 568A wiring is used when compatibility to telephone wiring systems (USOC) is needed. It is not recommended, as parts are not as commonly available.
PIN # COLOR SCREW TYPE PLATE
NOTE: This
is an RJ-45 wall plate (front view), T568A.
Crossover Cable - Connection PC to PC
There are 2 purposes to crossover cables:
Two computers are connected together by using a network interface card (NIC) in each computer and a crossover RJ-45 patch cable between them.
Below is the pinouts for the crossover cable.
| PIN # (one end) |
PIN # (other end) |
T568B color code |
| 1 | 3 | White/Orange |
| 2 | 6 | Orange/White |
| 3 | 1 | White/Green |
| 6 | 2 | Green/White |
NOTE: The following pins are OPTIONAL for Category 3 and MUST be connected for Category 5 (according to standard).
| 4 | 4 | Blue/White |
| 5 | 5 | White/Blue |
| 7 | 7 | White/Brown |
| 8 | 8 | Brown/White |
Hold the cable with both wires towards you and both tabs down. Look at the left 2 wires of each RJ-45 plug. If the wires are both the same (White/Orange on pin #1 and Orange/White on pin #1 of the second cable), then the cables are STRAIGHT THROUGH.
If one Pin #'s 1 and 2 are different on each plug (White/Green on Pin #1 and White/Orange on Pin #1 on the other RJ-45), then it is a crossover cable.
Below are 2 crossover RJ-45 plugs:
Please go to:
http://www.la-cable.com/how_to_network_pcs.htm
This is the most common way of having a network with one or more hubs that service multiple PC's. Hubs can be linked together to expand your system. Some hubs are limited to the number that can be added. Hubs are connected together with either:
A straight through RJ-45 patch cable is used to connect the file server to the hub and the hub to the individual PC work stations.