8p8c - wikipedia, the free encyclopedia

An 8P8C modular plug beforehaving been crimped onto a

cable

Connector and cable

8P8CFrom Wikipedia, the free encyclopedia

The 8P8C (8 Position 8 Contact, also backronymed as 8 position 8conductor; often incorrectly called RJ45) is a modular connector commonlyused to terminate twisted pair and multiconductor flat cable. These connectorsare commonly used for Ethernet over twisted pair, Registered jacks and othertelephone applications, RS-232 serial using the EIA/TIA 561 and Yoststandards, and other applications involving unshielded twisted pair, shieldedtwisted pair, and multiconductor flat cable.

An 8P8C modular connector has two paired components: the male plug and thefemale jack, each with eight equally-spaced conducting channels. On the plug,these conductors are flat contacts positioned parallel with the connector body.Inside the jack, the conductors are suspended diagonally toward the insertioninterface. When an 8P8C plug is mated with an 8P8C jack, the conductorsmeet and create an electrical connection. Spring tension in the jack's conductorsensure a good interface with the plug and allow for slight travel during insertionand removal.

Although commonly referred to as an RJ45 in the context of Ethernet andcategory 5 cables, it is technically incorrect to refer to a generic 8P8Cconnector as an RJ45. The registered jack (RJ) standard specifies a differentmechanical interface and wiring scheme for a true RJ45 than TIA/EIA-568-Bwhich is often used for modular connectors used in Ethernet and telephoneapplications. 8P8C modular plugs and jacks look very similar to the plugs andjacks used for FCC's registered jack RJ45 variants, although the true and extremely uncommon RJ45 is notcompatible with 8P8C modular connectors. It neither uses all eight conductors (but only two of them for a pair ofwires plus two for a programming resistor) nor does it fit into an 8P8C jack because the true RJ45 plug is "keyed".

Contents1 "RJ-45" naming confusion2 Standardization3 Wiring4 Types5 Termination6 Applications7 See also8 Notes9 References10 External links

11/7/2009 8P8C - Wikipedia, the free encyclopedia

http://en.wikipedia.org/wiki/8P8C 1/5

"RJ-45" naming confusionSee also: Registered jack naming confusion

Originally, there was only the true telephone RJ45. It is one of the many registered jacks, like RJ11, a standardfrom which it gets the "RJ" in its name. As a registered jack, true telephone RJ45 specifies both the physicalconnector and wiring pattern. The true telephone RJ45 uses a special,[1][2] keyed 8P2C modular connector, withPins 5 and 4 wired for tip and ring of a single telephone line and Pins 7 and 8 connected to a programming resistor.It is meant to be used with a high speed modem, and is obsolete today.

Telephone installers who installed true telephone RJ45 jacks in the past were familiar with the inner workings whichmade it RJ45, but their clients saw only a hole in the wall of a particular shape, and came to understand RJ45 as thename for a hole of that shape. When they found similar-looking connectors being used in entirely non-telephoneapplications, usually connecting computers, they called these "RJ45", too. This was therefore the so-calledcomputer "RJ45".

Compounding the problem was the fact that the physical connectors indicated by true telephone RJ45 are not evencompatible with computer "RJ45" connectors. True telephone RJ45 connectors are a special variant of 8P2C,meaning only the middle 2 positions have conductors in them, while pins 7 and 8 are shorting a programmingresistor. Computer "RJ45" is 8P8C - all eight conductors are always present. Furthermore, true telephone RJ45involves a "keyed" variety of the 8P body, which means it may have an extra tab that a computer "RJ45" connectoris unable to mate with.

Because true telephone RJ45 never saw wide usage and computer "RJ45" has become well known today,computer "RJ45" is almost always what a person is referring to when they say "RJ45". Electronics catalogs notspecialized to the telephone industry advertise 8P8C modular connectors as "RJ45". Virtually all electronicequipment that uses an 8P8C connector (or possibly any 8P connector at all) will document it as an "RJ45"connector.

Rounding out the confusion in "RJ45" naming is the fact that some people intend for the term to encompass not justthe connector shape and size, but the wiring standard for it described by TIA/EIA-568-B as well. So one might find"Here is the pinout of an RJ45 jack."

StandardizationThe shape and dimensions of an 8P8C modular connector are specified for U.S. telephone applications by theAdministrative Council for Terminal Attachment (ACTA) in national standard ANSI/TIA-968-A. This standarddoes not use the short term 8P8C and covers more than just 8P8C modular connectors, but the 8P8C modularconnector type is the eight position connector type described therein, with eight conductors installed.

For data communication applications (LAN, structured cabling), International Standard IEC 60603 specifies inparts 7-1, 7-2, 7-4, 7-5, and 7-7 not only the same physical dimensions, but also high-frequency performancerequirements for shielded and unshielded versions of this connector for frequencies up to 100, 250 and 600 MHz,respectively.

Wiring



Connectors are frequently terminated using the T568A or T568B pin/pair assignments that are defined in TIA/EIA-568-B. A cable that is wired as T568A at one end and T568B at the other (Tx and Rx pairs reversed) is a"crossover" cable. Before the widespread acceptance of auto-MDI/MDIX capabilities a crossover cable wasneeded to interconnect similar network equipment (such as hubs to hubs). Crossover cables are still used today toconnect two computers together without a switch or hub. A cable wired the same at both ends is called a "patch" or"straight-through" cable, because no pin/pair assignments are swapped.

TypesTwo types of 8P8C plugs and installation tools (used for crimping the plug onto a cable) are commonly available:Western Electric/Stewart Stamping (WE/SS) and Tyco/AMP. While both types look remarkably similar, thetooling used to install the two different plug types is mutually exclusive and cannot be interchanged between the twotypes. WE/SS compatible plugs are available from a large number of manufacturers, whereas Tyco/AMP plugs areproduced exclusively by Tyco Electronics. Both types of modular plugs will plug into the same standard 8P8Cmodular jack.

WE/SS and Tyco/AMP 8P8C plugs have different spacing for the cable strain relief.[3][4] As a result, using aWE/SS 8P8C crimp dieset on a Tyco/AMP 8P8C plug will crush the top of the connector, and vice versa. Whilethe WE/SS compatible plug is produced by a larger number of manufacturers than the Tyco/AMP plug, it is stillimportant to know what style is being used to avoid damaging the plug during crimping.

Both types of 8P8C plugs are available in shielded and unshielded varieties, depending on the attenuation toleranceneeded. Shielded plugs are more expensive and require shielded cable, but have a lower attenuation and can reducesignal noise.

TerminationTermination of a cable with an 8P8C plug involves using a hand crimper or crimp machine containing an 8P8C die-set or an A67T standard die-set. An 8P8C crimp die-set usually looks similar to an 8P8C jack, except for the eightteeth lining the top portion of the die. When the tool is operated, the die compresses around the 8P8C plug. As thedie compresses, these teeth force the plug contacts down into the conductors of the cable being terminated,permanently attaching the plug to the cable. The crimper may also permanently deform part of the plug body in sucha way that it grips the outer sheath of the cable. This helps to keep the plug securely fastened to the end of thecable, by providing strain relief.

Applications8P8C are commonly used in computer networking and telephone applications, where the plug on each end is an8P8C modular plug wired according to a TIA/EIA standard. Most network communications today are carried overCategory 5e or Category 6 cable with an 8P8C modular plug crimped on each end.

The 8P8C modular connector is also used for RS-232 serial interfaces according to the EIA/TIA-561 standard.[5]

This application is commonly used as a console interface on network equipment such as switches and routers.Other applications include other networking services such as ISDN and T1.

In floodwired[6] environments the center (blue) pair is often used to carry telephony signals. Where so wired, thephysical layout of the 8P8C modular jack allows for the insertion of an RJ11 plug in the center of the jack, provided



the RJ11 plug is wired in true compliance with the U.S. telephony standards (RJ11) using the center pair. Theformal approach to connect telephony equipment is the insertion of a type-approved converter.

The remaining (brown) pair is increasingly used for Power over Ethernet (PoE). Legacy equipment may use just thispair; this conflicts with other equipment as manufacturers used to short circuit unused pairs to reduce signalcrosstalk. Some routers/bridges/switches can be powered by the unused 4 lines — blues (+) and browns (−) — tocarry current to the unit. There is now a standardized scheme for Power over Ethernet.

Different manufacturers of 8P8C modular jacks arrange for the pins of the 8P8C modular connector jack to belinked to wire connectors (often IDC type terminals) that are in a different physical arrangement from that of othermanufacturers: Thus, for example, if a technician is in the habit of connecting the white/orange wire to the "bottomright hand" IDC terminal, which links it to 8P8C modular connector pin 1, in jacks made by other manufacturersthis terminal may instead connect to 8P8C modular connector pin 2 (or any other pin).

See alsoList of registered jacksRJ45ARJ45GG45TERA

Notes1. ^ http://www.hvs.on.ca/modular_jack_wiring.htm2. ^ http://www.siemon.com/us/standards/13-24_modular_wiring_reference.asp3. ^ "Stewart Connector 937-SP-3088 - Eight conductor/eight position line cord module

(http://www.belfuse.com/Data/Datasheets/CT300064.pdf) " (PDF). Glen Rock, Pennsylvania: Bel StewartConnector. 2006-02-01. http://www.belfuse.com/Data/Datasheets/CT300064.pdf. Retrieved 2009-09-10.

4. ^ "Tyco/AMP 5-554739-2 - Modular plug assembly, 8 position, flat oval cable(http://www.tycoelectronics.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Customer+Drawing%7F554739%7FP%7Fpdf%7FEnglish%7FENG_CD_554739_P.pdf) " (PDF). Harrisburg, Pennsylvania: Tyco Electronics Corporation. 2008-03-31.http://www.tycoelectronics.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Customer+Drawing%7F554739%7FP%7Fpdf%7FEnglish%7FENG_CD_554739_P.pdf.Retrieved 2009-09-10.

5. ^ http://www.zytrax.com/tech/layer_1/cables/tech_rs232.htm#rj456. ^ floodwire is a chiefly British term for installing communications cables in a massive fashion in anticipation of

their eventual use.

ReferencesANSI/TIA-968-A: Telephone terminal equipment – Technical requirements for connection of terminalequipment to the telephone network (https://www.part68.org/SecureDocuments/TIA-968-A-Final.pdf)IEC 60603-7-1: Connectors for electronic equipment — Part 7-1: Detail specification for 8-way, shieldedfree and fixed connectors with common mating features, with assessed qualityIEC 60603-7-2: Connectors for electronic equipment — Part 7-2: Detail specification for 8-way,unshielded, free and fixed connectors, for data transmissions with frequencies up to 100 MHz



IEC 60603-7-4: Connectors for electronic equipment — Part 7-4: Detail specification for 8-way,unshielded, free and fixed connectors, for data transmissions with frequencies up to 250 MHzIEC 60603-7-5: Connectors for electronic equipment — Part 7-5: Detail specification for 8-way, shielded,free and fixed connectors, for data transmissions with frequencies up to 250 MHzIEC 60603-7-7: Connectors for electronic equipment — Part 7-7: Detail specification for 8-way, shielded,free and fixed connectors, for data transmissions with frequencies up to 600 MHzISO/IEC 8877, EN 28877: Information Technology - Telecommunications and Information Exchangebetween Systems - Interface Connector and Contact Assignments for ISDN Basic Access InterfaceLocated at Reference Points S and T

External linksHow to Make a Network CableHow to wire a 10BaseT or 100BaseT connector with Category 5 cable and 8P8C modular connectors(http://www.alatec.com/info/rj45.html)Step by Step Instructions on How to Punch Down Category 5e Cable to a RJ45(http://www.cablesupply.com/Tutorials/Video/Cabling/PunchDownRJ45Jack.asp)How to create your own Ethernet Cables (http://www.ertyu.org/steven_nikkel/ethernetcables.html)TIA-968-A (http://www.part68.org/documents_order_disclaimer.aspx?ID=5) — Contains dimensions forjacks and plugs.Catalog page showing the difference between solid and stranded contacts (http://www.l-com.com/multimedia/catalog_page/lcom_082-06_Premium_Modular_Plugs.pdf)Diagram of RJ45S (http://www.siemon.com/us/standards/13-24_modular_wiring_reference.asp) showingthe difference between an 8P8C and a true RJ45 8-position keyed connector.Common Outlet Configurations (http://www.siemon.com/us/standards/13-25_common_outlet_configurations.asp) graphical representation of twisted pair pinoutUSOC RJ45S with programming resistor (http://www.hvs.on.ca/modular_jack_wiring.htm) has a differentshape than the computer "RJ45".RJ45 Pinouts and cables schematics (including network cables)(http://pinouts.ru/connector/8_pin_RJ45_male_connector.shtml)RJ45 Interactive Example (http://www.osischool.com/concept/communication/rj45)

Retrieved from "http://en.wikipedia.org/wiki/8P8C"Categories: Registered jacks | Networking hardware | Telephone connectors | Out-of-band management | Ethernet

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