The Fiber Optic Association

  The Fiber Optic Association, Inc.
the non-profit professional society of fiber optics

Reference Guide To Fiber Optics


Topic: Premises Cabling Jargon Table of Contents: The FOA Reference Guide To Fiber Optics


Cabling Jargon
The key to understanding any technology is understanding the language of the technology – the jargon. This page is an overview of cabling jargon to introduce you to the language of the technology and help you understand what you will be reading in this section. We suggest you read this section carefully to help your understanding of the rest of the pages and refer back to it when you encounter a term that you do not recognize.    

What is Premises Cabling?
By premises cabling, we mean the cabling used inside buildings (and in restricted geographic areas like campuses or among business facilities) that follows industry standards. Mostly we are refering to structured cabling systems defined by TIA-568 or ISO/IEC 11801  and related standards that are used for LANs, telephone systems and even other systems adapted to structured cabling like CCTV, security or building management. Other systems that depend on cabling such as security and building control are migrating to structured cabing for its widespread availability and predictability.


Here's an overview of the basic jargon used in cabling.
 
 
To begin with, what do we call this technology of cabling?
People call it lots of things:
VDV (for voice/data/video) cabling
Premises (e.g. indoor) cabling
Structured cabling (from the standards)
Data/voice cabling
Low voltage cabling (less than power cables)
Limited energy cabling (mostly harmless)
Teledata cabling (a made-up word from telecommunications and data)
Datacom cabling (an abbreviated version of data communications)
....but most people call it"premises cabling" for its application or "structured cabling" after the "568" standard.
Premises cabling is the infrastructure for telephone and LAN connections in most commercial installations and even in some modern homes. It's also used for fire alarms, building management, audio and video.
 
Structured Cabling is the standardized achitecture and components for communications cabling specified by the EIA/TIA TR42 committee and used as a voluntary standard by manufacturers to insure interoperability.
 
 
 
Cabling Standards
Structured cabling is based on a number of industry standards - voluntary interoperability standards - developed by manufacturers who want their products to work together. They meet in committees several times a year and decide on the specifications of their products. These common specs mean that equipment will work on any cabling system that follows the standards and most cabling components can be interchanged without adversely affecting performance.
 
EIA/TIA: In the US, Electronics Industry Alliance/Telecommunications Industry Association (TIA), an industry trade association that creates voluntary interoperability standards for the products made by member companies. Worldwide standards rely on ISO and IEC standards. More.
 
EIA/TIA 568: The main standard document for structured cabling, usually referred to as simply "568." It is now on the "C" revision, published in 2009. Worldwide, ISO/IEC 11801 is approximately the same as TIA-568. More

EIA/TIA 569: Covers pathways and spaces. Defines the "telecom closet" or telecom room as it is now called. (ISO/IEC 14763-2)
 
EIA/TIA 570: For residential cabling.
 
EIA/TIA 606: cabling system administration (documentation) (ISO/IEC 14763-1)
 
EIA/TIA 607: Grounding and bonding
 
Standards are not code! They are voluntary interoperability specifications. However every installation must be compliant to local building codes for safety!
 
NEC (National Electrical Code): written by NFPA (National Fire Protection Assn.) this code sets standards for fire protection for construction and is a legal requirement in most cities.
 
Structured Cabling Architecture
cabling architecture
 

Structured Cabling Terms:
The terms listed her are the traditional terms used since the beginning of structured cabling, but a new set of terminology is being introduced.
 
Telecom Closet (TC): The location of the connection between horizontal cabling to the backbone. Now often called "Telecom Room" to imply it's usually bigger than a closet!
 
Main Cross-Connect (MXC): The old telco term for the location of the main electronics in a building. LAN people may call it the equipment room
 
Intermediate Cross-Connect (IXC) : A room in between the TC and MXC where cables are terminated
(TIA has proposed to change these terms in future standards. Here are the new terms.)
 
Work Area Outlet: The jack on the wall which is connected to the desktop computer by a patchcord

Patch Panel: A rack or box where cables are terminated - usually in 110 punchdowns and interconected with patchcords
 
Horizontal Cabling: The connection from the telecom closet to the work area outlet (desktop)
 
Backbone Cabling: The cabling that connects all the hubs in telecom closets or MXCs together
 
Link (Permanent Link): The installed cable plant from work area outlet jack to the patch panel in the telecom closet
 
Channel: The cable plant including the link plus patchcords on either end to connect the communications hardware
 
Patchcord: A short length of stranded cable with a RJ-45 plug on either end, used to connect hardware to the link or to connect cables in a Patch Panel. Also a short fiber optic cable use for connections.
 
J hook: A hook shaped like the letter J used to suspend cables
 
Fishtape: Semiflexible rod used to retrieve cables or pull line
 
 
 
Cable
 
The Types Of "Low Voltage" Copper Cable. 
For information on fiber optic cabling, see the FOA Online Fiber Optic Reference Guide.
 
UTP: Unshielded twisted pair cable, most commonly comprised of 4 twisted pairs of copper conductors, graded for bandwidth as "Levels" (from Anixter) or "Categories" (EIA/TIA 568).  Legacy analog phone systems (POTS or plain old telephone systems) used multipair UTP cables with 25, 50, 100, 200 or more pairs.
 
Category 3,4,5, 5e, 6: Ratings on the bandwidth performance of UTP cable, derived from Anixter's Levels program. Category 5e (enhanced) is rated to 100MHz. Cat 6 standards for UTP are specified at up to 200 MHz. Cat 6A (augmented) up to 500 MHz has recently been ratified. Cat 7 is also discussed for the future, but is only standardized as "Class F" in Europe, not the US. "Categories" called "Classes" in woldwide standards like ISO and IEC.  Cables rated Cat 5 or higher are limited to 4 pairs.
 
A typical Cat 6 cable is shown below.
 
UTP
 
STP: Shielded twisted pair, specified by IBM for Token Ring networks and offered by some vendors in higher performance versions than UTP.

ScTP: Screened Twisted Pair, a UTP cable with an overall foil shield to prevent interference.

fiber optic cable
 
Optical Fiber: Both multimode and singlemode fiber are included as well. See Fiber Optics, The Basics in the FOA Online Reference Guide or  Lennie Lightwave's Guide to Fiber Optics for more information on fiber optics.
 
Coax: A type of cable that uses a central conductor, insulation, outer conductor/shield, and jacket; used for high frequency communications like CCTV (closed circuit TV) or CATV (community antenna TV or cable TV). Coax is not included in TIA-568 but is included in TIA-570 for home use.
coax
 
RG-6/RG-59: 75 ohm coax used for video. RG-6 is the standard for CATV, RG-59 is used on some short CCTV networks.
 
RG-58: 50 ohm coax used for "Thinnet" Ethernet.
 
HFC: Hybrid fiber-coax CATV network combines coax and optical fiber
 
 
Terminations
The connectors for UTP are also standard - used on every cable for Cat 3, 5, 5e, 6, but must be rated for the same performance level, e.g. Cat 6 hardware on Cat 6 cable.
UTP plug and jack
 
RJ-45: The popular name of the modular 8 pin connector used with UTP cable in structured cabling systems. It is used erroneously, as a connector is only really an RJ-45 if it is terminated with USOC pinout for plain old telephone service. 
 
Jack: The receptacle for a modular plug like the modular 8 pin connector, often used in large quantities in patch panels. (Left in the photo above)
 
Plug: The connector on the end of UTP cable. (Right in the photo above.)
 
Punchdown: A connecting block that terminates two cables directly, most often used for connecting incoming multipair cables to 4 pair cables to the desktop but occasionally for cross connecting 4 pair cables. 110 blocks are most popular for LANs, 66 blocks for telco, but some installers use BIX or Krone.
Below - 66 blocks on the left, 110 blocks on the right:
punchdowns
 
 
 
Copper Cable Testing
 
After installing the cables, they must be tested. Every cable, including Cat 3 for telephones, must be tested for wiremap, but cable certifiers will test for all the parameters listed below.
 
Wiremap: All eight wires must be connected to the correct pins, and the test is called a wiremap test.
 
Length: The length must be less than 90 m for the permanent link and less than 100 m for the channel
 
Attenuation: The reduction in signal strength due to loss in the cable.
 
NEXT: Near End Cross Talk, or the signal coupled from one pair to another in UTP cable.
 
ACR: Attenuation to crosstalk ratio, a measure of how much more signal than noise exists in the link, by comparing the attenuated signal from one pair at the receiver to the crosstalk induced in the same pair
 
Return Loss: Reflection from an impedance mismatch in a copper cable
 
ELFEXT: Equal level far end crosstalk; crosstalk at the far end with signals of equal level being transmitted.
 
Propagation Delay: The time it takes a signal to go down the cable.
 
DC Loop Resistance: The DC resistance of the cable in ohms.
 
Delay Skew: The maximum difference of propagation time in all pairs of a cable.
 
Power Sum Next: Near end crosstalk tested with all pairs but one energized to find the total amount of crosstalk caused by simultaneous use of all pairs for communication
 
Power Sum ElFEXT: ELFEXT for the sum of the other 3 pairs on the 4th pair.
 
PSACR: PowerSum ACR
Alien Crosstalk: Crosstalk from one pair in a cable to the equivalent pair in another cable, a problem with Cat 6A.
Fiber Testing: Testing optical fiber is much easier. One need only test the loss from one end to the other, as bandwidth or frequency response is not generally an issue for premises cabling. More on fiber testing.
 

Then There's The Electronics That Makes It All Work Over The Cabling As A Network
 
Hub: The electronic box that connects to all the horizontal cables which are them connected by backbone cabling, enabling any PC to talk to any other
 
Switch: A device like a hub but connects any two devices directly, allowing multiple connections simultaneously
 
Bridge: A device that connects two or more sets of network cables
 
Router: A smart switch that connects to the outside world
 
Ethernet:: A 10, 100 or 1000 Megabit per second local area network (LAN) that is by far the most popular LAN
 
10Base-T: 10 MB/s Base Band Transmission, 100 meters max, segment length on Cat 3, or better twisted pair cable
 
100Base-TX: 100 MB/s Base Band Transmission, 100 meters max, segment length on Cat 5, twisted-pair cable, also referred to as Fast Ethernet
 
1000Base-T: Gigabit Ethernet on Cat 5e UTP

10GBase-T: 10 Gigabit Ethernet on Cat 6A UTP

All versions of Ethernet also have fiber optic connection standards. More
 
Power over Ethernet: The IEEE 802.3 Ethernet committee added provisions for powering devices off the spare pairs in a 4-pair UTP cable. Since Ethernet up to 100Base-TX uses only pairs 2 and 3, pairs 1 and 4 are available to provide power. Pair 1 (pins 4/5) is the + conductor, pari 4 (pins 7/8) is the - conductor. Almost 13 watts of power are available, adequate for powering local swithches or hubs that can serve several users locally from one UTP cable, thus saving cabling costs.
 
Wireless Is NOT Wireless
Most LANs today include wireless access points. Wireless is by no means wireless, as it requires wiring to connect it to the network. It merely replaces patchcords with a wireless link to allow roaming within a limited area. Wireless requires many access points connected (over wire or fiber) into the backbone.
WiFi is the popular name for IEEE 802.11 standard used by most portable computers and many other mobile devices.
Bluetooth (IEEE 802.15) is a limited distance network for consumer devices. It has been used to connect a wireless printer or mouse to a PC, wireless headsets to cell phones and stereos, cell phones to cars for hands-free operation, digital cameras to printers, etc.
WiMAX (IEEE 802.16)  is a further development of wireless network technology that expands the data capacity of wireless and it’s distance capability.

 
Test Equipment and Tools For Cabling:
 
Digital multimeter: A simple tester that measures if the cable is shorted and whether or not it is open
 
Wire Mapper: Checks each wire to make sure they are terminated in the correct order
 
Cable Certification Tester: Tests everything, wiremap, length, attenuation and crosstalk in one connection, gives you a pass/fail result
Cable Verification Tester: A device that runs network signals over installed cabling to see if the cabling can transmit network data without error.
TDR: Time domain reflectometer, a testing device used for copper cable that operates like radar to find length, shorts or opens, and impedance mismatches
Fiber optics: Testing is done with visual tracers/fault locators,  optical loss test sets and OTDRs.  Here is more information on fiber testers.





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Table of Contents: The FOA Reference Guide To Fiber Optics


 


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