Voice & Data Wiring Knowledge Document
Diagrams and discussion about commonly encountered items.

Let's start with some of the false but generally used terms. Ninety-nine percent of the people that use them (including us) refer to the 8 pin modular phone/data plug ends as RJ45 plugs. RJ45 is actually a wiring scheme rather than a type of device. Don't worry about it though, if you ever call a supply house to order a RJ45 jack or plug, they'll know exactly what you're talking about. Even Microsoft refers to them in their official training manuals as RJ45. Hmmm. While we're on the topic, a 4 or 6 position plug or jack is not actually RJ11... well, it can be, but it depends on how it's wired. Read below for the details. It is important to know RJ11 wiring vs RJ14.

Jack Positions USOC RJ61 T568A T568B (AT&T) 10BASE-T (LAN) 1 wht/brn wht/grn wht/org wht/blue 2 wht/grn grn/wht org/wht blue/wht 3 wht/org wht/org wht/grn wht/org 4 blue/wht blue/wht blue/wht   5 wht/blue wht/blue wht/blue   6 org/wht org/wht grn/wht org/wht 7 grn/wht wht/brn wht/brn   8 brn/wht brn/wht brn/wht

Here is a diagram for normal T568B wiring of cat5 cabling.

Here is how a crossover cable is wired.

Jacks and plugs are wired to conform to Uniform Service Ordering Code ("USOC") numbers, originally developed by the Bell System, and endorsed by the FCC. One specific piece of hardware can be wired in different ways, and have different USOC numbers. USOC has become an acronym, pronounced "you-sock," and jack wiring schemes are generally referred to as "USOC codes." Each of the basic jack styles can be wired for different RJ configurations. For example, the 6-position jack can be wired as an RJ11C (1-pair), RJ14C (2-pair), or RJ25C (3-pair) configuration. An 8-position jack can be wired for configurations such as RJ61C (4-pair) and RJ48C. The keyed 8-position jack can be wired for RJ45S, RJ46S, and RJ47S. The fourth modular jack style is a modified version of the 6-position jack (modified modular jack or MMJ). It was designed by Digital Equipment Corporation (DEC) along with the modified modular plug (MMP) to eliminate the possibility of connecting DEC data equipment to voice lines and vice versa.

 Here are the most common USOC configurations.

RJ11 Jack

RJ14 Jack

RJ25 Jack

RJ31x Jack

RJ61 Jack

RJ48x Jack

RJ45s Jack

RJ48s Jack

Local Area Network Standards designed to operate over UTP designate pin/pair assignments on modular connectors for signal transmission. While the TIA/EIA configurations (T568A and T568B) support all of these designations, there are some cases where the user chooses to cable only the number of pairs required to support the applications. While wiring a residence where the amount of cable run by the builder is limited, the installer may choose to wiring a particular jack using 2 pairs/10BT and save the last 2 pairs for phone or another data jack. We have been forced to do this on many occasions.

Here are the 2 common data wiring formats most commonly used.

T568A Wiring

T568B Wiring (Most common)

10 Base T

Token Ring

TP-PMD

1000 Base T

Below is the wiring scheme to punch down a 25 pair cable to a 66 or 110 block.
 If you're ever trying to get a rise out of a pissed off old telephone guy,
 be sure to refer to the wire colors as they "are" and not as they
 are technically referred to.  For example, call the Violet "purple".
 (This is a great test to see just how much of an ass that phone guy is!)

Here are some common data wiring questions that we are often asked by our customers.

What is Category 5, 5e & 6 (CAT-5, CAT-5e CAT-6)?
This is a performance designation standards laid out by TIA/EIA for twisted pair cable and connectors specified up to 550 MHz and data rates of 1000 Mbps. The current standard is TIA/EIA 568.

Cat-5 performs at up to 100MHz while Cat 5e performance reaches up to 350MHz. Cat-6 cable is rated up to 550Mhz.

Category 5 , Category 5e and Category 6 cable consist of 4 pair unshielded twisted pair (UTP) with 100ohm impedance and electrical characteristics supporting transmissions up to 550 MHz.

Cat-5e (350MHz) and Cat-6 (550MHz) improve on the original Cat-5 (100MHz) design by adding more shielding through extra twists to the wire. Cat-6 places a divider inside the inner core to separate the wire pairs even more than Cat-5e. This divider reduces cross talk (NEXT) between the wire pairs.

The real differences between Category 5, Category 5e and Category 6 cabling are in transmission performance. Category 5e and Category 6 cables are most suitable for a higher-speed Ethernet 100base-T and 1000base-T (Gigaspeed). Gigabit Ethernet applications reaching 1000 Mbps should use Category 6 cabling for best results.

What's the difference between PVC and PLENUM Cable?
The reason for these two types of cable are for fire code safety standards of different types of buildings. Both cable types have the same speed performance.

PVC stands for Poly Vinyl Chloride, which is the outer insulation jacket used around the copper wires. When it burns, it emits a poisonous smoke (think burning plastic). While, Plenum Rated jackets, a TEFLON® product, burns at a much higher temperature and is not nearly as toxic.

So, When should I use PVC and when should I use Plenum Rated Cable?
PVC cable is about 1/3 the price of Plenum Rated cable. PVC can be used in almost all inside wall or floor applications in home or business/commercial settings. PVC is used in well over 90% of all cabling applications.

Plenum rated cable is used in commercial building air Plenum ceilings where the return air is forced through the ceiling (may include drop down ceilings), rather than being ducted through air conditioning tubes. Thus Plenum cable must be used in this situation to prevent toxic smoke from being flushed through the whole building in the event of a fire.

If you are unsure if you need to upgrade to Plenum cable you should check with the Building and Safety Department of your City or the building engineer. Different cities have different regulations.

What's the fastest, best cable for me. Should I upgrade to CAT-6 Cable?
This is a very tricky question to answer. Usually a CAT5E 350MHz cable will work great for most applications. However, Cat6 cable allows for less packets lost during transmission due to the higher signal to noise ratio and the lower cross talk (NEXT) level. Thus giving faster network speeds. However, if your network isn't transfering large amounts of data, the "real world" difference may be negligible. Also, if your intended use is sharing a broadband modem the limitaion is typically more in your connection speed rather than the cable attached from computer to the modem.

What the difference between Ethernet cable, Straight-through, and Patch Cables?
Absolutely nothing. These three terms are synonymous when talking cable, although typically a patch cable is made with stranded copper cable so it can bend and flex without eventually breaking or degrading the copper inside as will solid copper core wire.

Category 5 vs. Category 5 Enhanced (5E)
Cat-5 is an old standard, most cable manufactures don't even make it anymore. Cat-5E is what should be used in today's higher speed networks. Cat-5E is fully backwards compatible with almost all Cat-5 products and networks. Cat-5E builds on the old Cat-5 design but adds more twists to the wire pairs to allow for higher transmission speeds up to 3 1/2 times that of the old Cat-5 cable...from 100MHz to 350MHz!!

Although Cat-5 may work there is no reason NOT to spend a few more dollars on a better, cleaner operating cable...Cat-5E or even Cat-6

Copper RJ-45 vs. Gold plated RJ-45 (50µ & 3µ)
Most people don't realize there are differences in the end connectors called RJ-45 8p8c plugs. They may all appear to look a like but the difference lies in which materials make up the contacts. Some are made with Copper while others are plated with Gold. As you may have guessed Gold is the best contact material used... but here is the catch! There are different concentrations of Gold plugs. Some are 3µ (3 microinches) of Gold while the best are 50µ (50 microinches) of Gold. 50µ is almost 20 Times as thick as 3µ plugs!

Never buy a cable with only 3µ of Gold (wears off quickly) or worse a Copper connector. Good cables (Cat 5E & Cat 6) will have 50µ Gold plating. Warning!! If the advertisement doesn't state 50µ Gold Plating then THEY ARE NOT!! If it only states "Gold plated" then chances are it's only 3µ Gold which will wear off after only a few times plugging them in and out of the socket.

What is a Crossover Cable?
A crossover cable is a segment of Category 5 (5e) cable that crosses over pins 1&2 and pins 3&6. This cable is normally used to connect two PCs (Peer to Peer) without the use of a hub or router. One cable hooks directly into the back of both computers using a standard 10/100BASE-T Ethernet Network Interface (NIC) card with RJ-45 ports.

What is the difference between 10BASE-T, 100BASE-T and 1000BASE-T?
10BASE-T is the IEEE standard that defines the requirement for sending information at 10 Mbps on unshielded twisted-pair cabling, and defines various aspects of running Ethernet on this cabling. Most Broadband cable modems and gaming system adhere to this standard.

100BASE-T is the IEEE standard that defines the requirement for sending information at 100 Mbps on unshielded twisted-pair cabling, and defines various aspects of running baseband Ethernet on this cabling.

1000BASE-T (Gigaspeed Network) is the IEEE standard that defines the requirement for sending information at 1000 Mbps on unshielded twisted pair cabling, and defines various aspects of running baseband Ethernet on this cabling.