Blue
Orange
Green
Brown
A Quick reference Survival Guide to cable and wiring for data and telephone networks, including telephone, UTP and Optic Fiber connectors.
datacommunication / network cable consisting of 4 'twisted' pairs of copper wire. (= 8 wires).
typical connector : RJ45 : 8 pins modular connector
| Wire pair #1: | White/Blue Blue |
|
| Wire pair #2: | White/Orange Orange | |
| Wire pair #3: | White/Green Green | |
| Wire pair #4: | White/Brown Brown |
In an 8 pin connector, seen from the front of the plug, where the contact points are, the typical pin-out is
1 - Orange/White (pair 2)
2 - Orange (pair 2)
3 - Green/White (pair 3)
4 - Blue (pair 1)
5 - White/Blue (pair 1)
6 - Green (pair 3)
7 - White/Brown (pair 4)
8 - Brown (pair 4)
This is a "T568B" pinout, the standard for horizontal cabling in structured wiring. There's an alternative pin-out, T568A. The only difference between T568A and T568B is that pairs 2 and 3 (orange and green) are swapped. The electrical characteristics are slightly different, but both types are interchangable in terms of connectivity.
To remember it : pair 1 (blue) in the middle, pair 3 (green) around it, pair 2 and 4 at the edges.
For 10BaseT, only pairs 2 and 3 (orange, green) are used : 1 pair to transmit, 1 to receive. Faster Ethernet protocols (gigabit ethernet) require all 4 pairs.
As 10BaseT only uses 2 pairs, it is possible to split 1 utp cable over 2 jacks (2 pairs/4 wires each, only pins 1-2-3-6). Can be used to save cable or improvise a solution when you lack cables, but I wouldn't recommend it. Upgrading to faster ethernet becomes a nightmare, and it complicates things. I don't like unnecessary complexity.
This is verified for Belgian Telecom - your mileage may vary.
A telephone cable typically has 4 wires - so two pairs : green (T) + red (R), and black(T) + yellow (R). A 'telephone line' requires 1 pair. Green and Red form pair 1 so the red and green wire will be your telephone line. In modular connectors, this pair is connected in the middle of the plug /jack (i.e. pins 4-5 in an RJ45 outlet, e.g. in your patch pannel, or pins 2 and 3 in a 4 pin modular connector. You can plug an RJ11 plug into an RJ45 jack (outlet)). Green + Red therefore correspond to the blue pair in an 4 pair UTP cable.
The 2nd pair can be used for a 2nd line, for power supply, or for more complex configurations. .
Your typical phone cable wil have 4 wires, with the following pinout :
1 - Black - pair 2
2 - Red - pair 1
3 - Green - pair 1
4 - Yellow - pair 2
So that is : pair 1 in the middle, pair 2 around it. 6-wire cable would have the 3th pair around the 2nd, but I've never seen those.
A "cheap" 10baseT construction (with only pins 1-2-3-6 connected) can not accommodate telephone, as pins 4-5 (the middle pins) are not connected. A workaround is then to connect a telephone pair to pins 4 and 5 in a jack that already has pins 1-2-3-6 for datacommunication. You save 1 pair of copper wires and add more work and lots of unnecessary complexity. Think again ...
This is verified for Belgian Telecom - your mileage may vary.
traditional Belgium phone plugs look like this. Traditionally, they'd be hard-wired with screw connectors. More recently, they have a modular (4 pin) adaptor build in. Same goes for outlets. To wire the screw-type plug/outlet, and sometimes the POTS Network Interface, you need to understand the indications inside it. (That's why modular connectors are so convenient - no hassle, just plug in)
The 4 pins are divided as follows :
2 screw contacts on the left (wall outlet or plug seen from the back), marked "a" and "b". Here you connect pair 1 (From what I've seen, I guess it's red on "a", green on "b")
2 screws on the right (marks seem to vary : E, s, ground, ...) - can (presumably) be used for a second line on the same outlet, or for whatever the 2nd pair is used for in your configuration.
If you use UTP or have cable with a different color scheme, you'll have to work out some sort of translation table between the pairs/colors to get every wire connected correctly. Consistency throughout your network helps, and avoids having to check, test, check again, try, try something else, ... with every wire you connect.
While in a home installation your telephone company might bring in just a 2 pair cable, larger installations require multiple phone lines and the telepghone company will use a multi-cable, a cable consisting of 20 or more pairs - with each pair a possible telephone line.
They typically use punchdown connectors (like this) to which those pairs are connected to the pairs in your building. You need a punchdown tool to connect wires to them. There may be standards as to which pair (colors) go where. These punchdown connectors can be uses do directly connect your wiring to the incoming pairs. An alternative method is that the incomming pairs are terminated on 1 block, your wiring on another bmock, and straps (jumpers) between the to blocks are used to 'patch' the pairs. Take notes, so that in the end, you know which pair connects to whitch telephone number, and from which outlet on your patch pannel you can reach it :-) .
RJ11, RJ45 are Registered Jacks - standard modular connectors. A more precise naming convention is of the form 6P2C - a 6 Positions (pins) connector in which 2 pins (in the midlle) are connected (have wires). That would be an RJ11, a typical (modular) telephone plug. See link to wikipedia below. Likewise, an RJ45 twisted pair (ethernet) connector would be P8C8 : 8 pins, all connected.
With Fiber Optics, the signal travels through an optic fiber and you typically have 1 fiber to send, 1 to receive. Collors usually don't matter, but there's a multitude of connector types and when ordering jumpers, pigtails, or devices such as GBICs or other media convertors, you'll have to know which one will fit.
The connector types (apparently) refer to the form factor of the connector itself and the mechanism used to connect a male into a female. The shape of the conductor is a factor in insertion loss etc but (apparently) does not determine the connector type. Jumpers (patch chords) can have different connectors at each end, eg to match an SC outlet on a patch panel to an LC outlet on a device (such as an HP mini-GBIC) - in which case you'd need an SC-LC patch chord.
| Connecter | Mode | male | Comments (mostly from "Black Box Explains ...) |
| SC | mono |   |
The SC connector features a molded body and a push- pull locking system. |
| ST | mono |   |
The ST connector uses a bayonet locking system. |
| ST | multi |   |
|
| LC | mono |  |
The LC connector, a small-form factor connector, features a ceramic ferrule and looks like a mini SC connector. It can be detached and attached easily because of the latch clip design (similar to that of the standard RJ45 plug) |
| FC | mono |  |
The FC connector is a threaded body connector. The connection is made by the metal threaded coupling nut being screwed into place. Used in high-vibration environments. |
| MTRJ | multi |  |
The MT-RJ connector, a small-form RJ-style connector, features a molded body and uses cleave-and-leave splicing. Primarily intended for desktop use - the form factor is based on the wellknown RJ45 or RJ11 connector. |
