UTP Cabling
LAN cables are generically called UTP (Unshielded Twisted Pair) and are identified with a category rating. When installing new cable, unless there is a very good reason not to, you should be using category 5e or 6 UTP which is rated for 10mb, 100mb or Gigabit LAN operation. UTP comes in two forms SOLID or STRANDED. SOLID refers to the fact that each internal conductor is made up of a single (solid!) wire, STRANDED means that each conductor is made up of multiple smaller wires. Stranded cable (which is typically more expensive) has a smaller 'bend- radius' (you can squeeze the cable round tighter corners with lower loss) and due to its flexibility should be used where you plug and unplug the cable frequently. All other things being equal, the performance of both types of cable is the same. In general, solid cable is used for backbone wiring and stranded for PC to wall receptacle (patch) cables.
RJ 45 Plug
The RJ45 plug is an 8-position modular connector that looks like a large phone plug. There are a couple variations available. The primary variation you need to pay attention to is whether the connector is intended for braided or solid wire. For braided/stranded wires, the connector has sharp pointed contacts that actually pierce the wire. For solid wires, the connector has fingers which cut through the insulation and make contact with the wire by grasping it from both sides. The connector is the weak point in an ethernet cable, choosing the wrong one will often cause grief later. If you just walk into a computer store, it's nearly impossible to tell what type of plug it is. You may be able to determine what type it is by crimping one without a cable.
RJ45 jacks come in a variety styles intended for several different mounting options. The choice is one of requirements and preference. RJ45 jacks are designed to work only with solid cable. Most jacks come labeled with color codes for either T568A, T568B or both. Make sure you end up with the correct one.
RJ45 jacks come in a variety styles intended for several different mounting options. The choice is one of requirements and preference. RJ45 jacks are designed to work only with solid cable. Most jacks come labeled with color codes for either T568A, T568B or both. Make sure you end up with the correct one.
Straight and cross over cable
There are two basic cable pin outs. A straight through cable, which is used to connect to a hub or switch, and a cross over cable used to operate in a peer-to-peer fashion without a hub/switch. Generally all fixed wiring should be run as straight through. Some ethernet interfaces can cross and un-cross a cable automatically as needed, a handy feature.
Increasing category levels are backward compatible.
Manufacturers will often test and certify their cable well beyond the standards.
*10GBase-T should work on most Cat 5e & 6, but to get the full 100m range, Cat 6a or greater is required.
Below is a picture of an UTP outlet showing both A & B type pinout. Just follow the colour code to terminate the cable onto the outlet. Ensure you follow the same standard (A or B) on all outlets.
Increasing category levels are backward compatible.
Manufacturers will often test and certify their cable well beyond the standards.
*10GBase-T should work on most Cat 5e & 6, but to get the full 100m range, Cat 6a or greater is required.
Below is a picture of an UTP outlet showing both A & B type pinout. Just follow the colour code to terminate the cable onto the outlet. Ensure you follow the same standard (A or B) on all outlets.
Pin number designations for T568BNote that the odd pin numbers (1, 3, 5 and 7) are always the white with a stripe of color. The wires connect to RJ-45 eight-pin connectors as shown below:
The color codes for T568B:
Pin 1: white/orange (pair 2) TxData +
Pin 2: orange (pair 2) TxData -
Pin 3: white/green (pair 3) RecvData+
Pin 4: blue (pair 1)
Pin 5: white/blue (pair 1)
Pin 6: green (pair 3) RecvData-
Pin 7: white/brown (pair 4)
Pin 8: brown (pair 4)
Note that the blue pair is on the center pins; this pair translates to the red/green pair for ordinary telephone lines which are also in the centre pair of an RJ-11 (green=white/blue, red=blue).
The color codes for T568A:
Pin 1: white/green (pair 3) RecvData+
Pin 2: green (pair 3) RecvData-
Pin 3: white/orange (pair 2) TxData +
Pin 4: blue (pair 1)
Pin 5: white/blue (pair 1)
Pin 6: orange (pair 2) TxData -
Pin 7: white/brown (pair 4)
Pin 8: brown (pair 4)
The T568A specification reverses the orange and green connections so that pairs 1 and 2 are on the center four pins, which makes it more compatible with the telephone company voice connections. (Note that in the RJ-11 plug at the top, pairs 1 and 2 are on the center four pins.)
The color codes for T568B:
Pin 1: white/orange (pair 2) TxData +
Pin 2: orange (pair 2) TxData -
Pin 3: white/green (pair 3) RecvData+
Pin 4: blue (pair 1)
Pin 5: white/blue (pair 1)
Pin 6: green (pair 3) RecvData-
Pin 7: white/brown (pair 4)
Pin 8: brown (pair 4)
Note that the blue pair is on the center pins; this pair translates to the red/green pair for ordinary telephone lines which are also in the centre pair of an RJ-11 (green=white/blue, red=blue).
The color codes for T568A:
Pin 1: white/green (pair 3) RecvData+
Pin 2: green (pair 3) RecvData-
Pin 3: white/orange (pair 2) TxData +
Pin 4: blue (pair 1)
Pin 5: white/blue (pair 1)
Pin 6: orange (pair 2) TxData -
Pin 7: white/brown (pair 4)
Pin 8: brown (pair 4)
The T568A specification reverses the orange and green connections so that pairs 1 and 2 are on the center four pins, which makes it more compatible with the telephone company voice connections. (Note that in the RJ-11 plug at the top, pairs 1 and 2 are on the center four pins.)