Modular connector

This article is about modular connectors. For the registered jack (RJ) wiring standard, see registered jack.

Left to right, modular connectors: 8P8C plug, 6P6C plug, 6P4C plug, 4P4C plug, 6P6C jack.

An 8P8C modular plug. This is the common crimp type plug, of the same kind pictured above crimped onto a cable (with moulded sleeve)

Modular connector is the name given to a family of electrical connectors originally used in telephone wiring. Even though they are still used for that purpose they are used for a variety of other things as well. A modular connector's advantage over many other kinds include small size and ease of plugging and unplugging. However the plastic retaining spring clip tends to get broken off when cables are pulled from storage for use. If that happens, the plug can easily fall out of the wall jack. Many uses that originally used a bulkier connector have migrated to modular connectors. Probably the most well known applications of modular connectors is for telephone jacks and for Ethernet jacks, which are nearly always modular connectors.

Modular connectors are used in the registered jack system, so some uses are precisely described by the registered jack specifications to specify how the connectors are wired for practical use in telecommunications. A notable exception that has no RJ specification is a 4P4C terminated telephone handset cable. The registered jack specifications define the wiring patterns of the jacks, not the physical dimensions or geometry of the connectors of either sex. Instead, these are covered by ISO standard 8877, first used in ISDN systems.

It is important to note that connector plugs are made for solid or stranded wire, especially when using 8P8C connectors for Ethernet cables. A plug for one wire type (especially stranded) might not make reliable contact when crimped to a cable with wires of the other type (See below).

Nomenclature

Main article: Registered jack naming confusion

Modular connectors also go by the names "modular phone jack/plug", "RJ connector," and "Western jack/plug."

It is very common, but incorrect, to use a registered jack number to refer to the physical connector itself; for instance, the 8P8C modular connector type is often loosely called RJ45 (for a standard that uses this connector), but 8P8C connectors are also used with different wiring, such as for Ethernet over twisted pair; in fact, the RJ45 wiring pattern is almost obsolete.

The term "modular connector" is not terribly descriptive, but arose from its original use in a novel system of cabling designed to make telephone systems more modular. This includes the 4P4C handset connector which is often referred to as an RJ9 or an RJ22—both of these are incorrect, since 4P4C connectors were not used to connect to carrier circuits at all: there is no valid registered jack number for the 4P4C. Citations to government document standards, that also define the RJ specifications, that explicitly disqualify a 4P4C (or 10P10C) connector as a registered jack, are vacuous, since currently, (circa 2010) any such RJ specification is simply absent in the official documents.

History

Modular connectors were originally invented and patented by Bell Telephone Laboratories (patent filed 6 July 1973; U.S. patent 3,860,316 issued 14 January 1975), and replaced the hard-wired connections on most Western Electric telephones around 1976. At the same time, they began to replace screw terminals and large 3 and 4 pin jacks in buildings.

Gender

Modular connectors have gender: male connectors are called plugs, while female connectors are called jacks or, sometimes, sockets.

The choice of gender is generally based on the location of the connector: plugs are used to terminate loose cables and cords, while jacks are used for fixed locations on surfaces such as walls and panels. (This is in contrast to some other connector systems, where the choice of gender is based on the function of the connector: for example, in power cabling systems, female connectors deliver power, while male connectors receive power.) Cables with a plug on one end and a jack on the other are rare (though telephone extension cables are very common); instead, cables that have the more common arrangement of plugs on both ends are connected using a male-to-male adapter, which has two jacks.

Locking and hook

Modular connectors are designed to lock together. A spring-loaded tab called a "hook" on the plug snaps into a jack so that the plug cannot be pulled out. To remove the plug, the hook must be depressed. The most common way to install a jack in a wall or panel is with the hook side down. This usually makes it easier to operate the hook when removing the plug, because the person grabs the plug with thumb on top and presses the hook with the index finger.

The modular connector suffers from a design flaw however, as the fragile hook easily snags on other cables and breaks. In this case, the connector is still basically functional as it can be slotted back into the jack, but the crucial locking feature is lost. Some higher quality cables have a flexible sleeve called a "boot" over the plug, or a special hook design, to prevent this. These cables are often marketed as "snagless". Boots are seen mainly on 8P8C data cables.

Sizes and contacts

8P8C modular plug pin positioning

8P8C plug with contacts for solid wire (left) and stranded wire (right)

contacts for solid wire (top left) and stranded wire (bottom right)

Modular connectors have positions, some or all of which have contacts in them, some or all of which have wires attached; positions with omitted contacts or contacts unattached to wires are unused for the electrical connection, but ensure that the plug fits correctly. For instance, RJ11 wires usually have connectors with 6 positions and 4 contacts, to which are attached 2 wires.

Modular connectors come in four sizes: 4-, 6-, 8-, and 10-position, where a position is a location for a contact. Not all of the positions may have contacts: when contacts are omitted, they are typically done so from the outermost two contacts inward, such that the number of contacts is always an even number. Unlike 4P and 6P connectors which have uniquely different widths, connectors that are 8P or 10P have identical widths.

The connectors are typically designated using two numbers that represent the quantity of positions and contacts, with each number followed by a "P" and "C", respectively: for example, "6P2C" for a connector having 6 positions and 2 contacts. Alternate designations omit the "P" and "C" while separating the position and contact quantities with either an "x" ("6x2") or a slash ("6/2"). It is interesting to observe that an 8P8C actually has almost the same form factor and profile as a 10P10C only missing pins 1 and 10 but not the positions. This means a 10P10C connector wired using only pins 2 thru 9 (a 10P8C) will function as an 8P8C connector.

Internally, the contacts have sharp prongs that when crimped, pierce the insulation and connect with the wire conductor. Ethernet cables, in particular, may have solid or stranded wire conductors and the sharp prongs are different in the 8P8C connectors made for each type of wire. A solid wire connector often has 3, slightly splayed, prongs on each contact to securely surround and grip the conductor. Stranded wire connectors have prongs that are designed to penetrate the wire strands to make a connection.

The dimensions of the connectors are such that a plug can be inserted into a jack that has more positions than the plug, leaving the jack's outermost contacts unterminated. However, not all plugs from all manufacturers have this capability, and some jack manufacturers warn that their jacks are not designed to accept smaller plugs without damage.

When all of the positions have contacts, the contacts are numbered sequentially starting from 1. When viewed head-on with the retention mechanism on the bottom, jacks will have contact number 1 on the left and plugs will have it on the right. If the connector has positions that do not have contacts, the remaining contacts are numbered as if all of the positions had contacts: for example, on a 6-position, 2-contact plug, where the outermost four positions do not have contacts, the innermost two contacts are numbered 3 and 4.

Some modular connectors are indexed: their dimensions are intentionally non-standard, preventing connections with connectors of standard dimensions. The means of indexing may be non-standard cross-section dimensions or shapes, retention mechanism dimensions, or retention mechanism quantity.

Pinouts

See also: registered jack, Ethernet over twisted pair, and RS-232 § Pinouts

Contact assignments, or pinouts, vary by application. While standardized for telephone applications by registered jack standard, and Ethernet over twisted pair by the TIA/EIA-568-B standard, there may be no standardization within an application: for example, there are multiple conventions for use of 8P8C connectors for RS-232.

For this reason, D-sub-to-modular adapters are typically shipped without the D-sub contacts (pins or sockets) terminated, so that the D-sub-to-modular contact pairing can—and must—be performed by the end-user.

4P4C

4P4C modular connector on a handset cable

Wired telephone using 4P4C connectors

The 4P4C connector, an Acronym for 4 Position, 4 Conductor (Sometimes the "C" is referred to as a Contact, though it actually stands for Conductor). While the "tine" is a contact, the name comes from the bandwidth that the cable will allow. A 4P4C will allow up to 4 Conductors, even though the connector itself has tines commonly referred to as Contacts); it is popularly, but incorrectly, called RJ22, RJ10, or RJ9. It is also commonly referred to as a "Handset Connector" because of the most popular usage for the connector. It is the de facto industry standard for wired telephone handsets. It is used to provide connection from the base of the telephone to the handset.

"RJ" stands for registered jack, a family of telephone connection standards. This handset connector is actually not a registered jack at all, since it was never intended to connect directly to the telephone service lines: RJ connects a phone to the service lines, while 4P4C connects two parts of a phone. It uses the 4P4C modular connector, which has four pins or electrical connections per connector. While all other RJ connectors are in use, and used in the field, by telephone companies, the 4P4C is unique in that it is for an End User only application, mainly from the phone to the handset.

Wiring

When a cable assembly consisting of a 4P4C connector and a 4-conductor cable is used for connecting a telephone handset to the telephone base; and the 4-conductor cable is wired to the connector and to the handset elements in a straight-through (non-crossover) manner, the wiring method shown in the diagram is in effect. In this case, the handset's speaker (the transducer) functions normally, even though its polarity is reversed; but the electret microphone used in most modern handsets will not function normally, because an electret microphone is polarity dependent.

However, if the wire pair for the handset transducer and the wire pair for the handset microphone are each wired in a crossover arrangement, then both the transducer and microphone will function correctly; even if the handset has an electret microphone. Most telephone handset cords (cable assemblies) are wired this way.

The vast majority of telephones that were made until around 1985 had a carbon microphone in the handset. Since a carbon microphone is not polarity sensitive, the cable assembly connecting this type of handset to the telephone base can use either straight-through or crossover wiring.

The impedance of the handset transducer is usually at least 100 Ohm, much greater than the impedance of the typical home loudspeaker: 8 Ohm.

Data port

The Macintosh 128K, Macintosh 512K and Macintosh Plus from Apple used 4P4C connectors to connect the keyboard to the main computer housing. The connector provided power to the keyboard on the outer two conductors and received data signals on the inner pair. The cable between the computer and the keyboard was a coiled cord with an appearance very similar to a telephone handset cable. The connector wiring, however, required a polarized straight through pinout. Using a telephone handset cable instead of the supplied cable could short out the +5 volt DC supply and damage the computer or the keyboard.

Some consumer equipment such as DirecTV set top boxes include a 4P4C low-speed data port connector. Such connectors can be adapted for use with a computer's serial port so that control commands can be sent from the computer to the set top box.

6P6C

6P4C crimp-on style connector

The 6P2C, 6P4C, and 6P6C modular connectors are probably most well known for their use as RJ11, RJ14, and RJ25 registered jacks respectively.

RJ11 is a physical interface often used for terminating telephone wires. It is probably the most familiar of the registered jacks, being used for single line POTS telephone jacks in most homes across the world.

RJ14 is similar, but for two lines, and RJ25 is for three lines. RJ61 is a similar registered jack for four lines. The telephone line cord and its plug are more often a true RJ11 with only two conductors.

Modular plugs are described as containing a number of potential contact "positions" and the actual number of contacts installed within these positions. RJ11, RJ14, and RJ25 all use the same six-position modular connector, thus are physically identical except for the different number of contacts (two, four and six respectively).

RJ11 wiring

6P6C connector showing the location of pin 1

Cables sold as RJ11 often actually use 6P4C RJ14 connectors (six position, four conductor), with four wires running to a central junction box. Two of its six possible contact positions connect tip and ring, and the other two conductors are then unused. 6P2C and 6P6C can also be found in stores.

The conductors other than the two central tip and ring conductors are in practice used for various things such as a ground for selective ringers, low voltage power for a dial light, or for 'anti-tinkle' circuitry to prevent pulse dialing phones from ringing the bell on other extensions. With tone dialing, anti-tinkle measures are not required.

Pinouts

Holding the connector in your hand tab side down with the cable opening toward you, the pins are numbered 1–6, left to right.

Position	Pair	T/R	±	RJ11	RJ14	RJ25	Twisted pair colors	25-pair colors	Old colors[a]	German colors[b]	Australian colors
1	3	T	+			T3	white/green	white/green	white	pink	orange
2	2	T	+		T2	T2	white/orange	white/orange	black	green	red
3	1	R	-	R1	R1	R1	blue	blue/white	red	white	blue
4	1	T	+	T1	T1	T1	white/blue	white/blue	green	brown	white
5	2	R	-		R2	R2	orange	orange/white	yellow	yellow	black
6	3	R	-			R3	green	green/white	blue	gray	green

• ^[a] While the old solid color code was well established for pair 1 and usually pair 2, there are several conflicting conventions for pair 3 (and sometimes even pair 2). The colors shown above were taken from a vendor of "silver satin" flat 8-conductor phone cable that claims to be standard. 6-pair solid (old) bellwire cables previously used by the Bell System use white for pair 3 tip but some vendor's cable may substitute orange for white. At least one other vendor of flat 8-conductor cable uses the sequence blue, orange, black, red, green, yellow, brown and white/slate.
• ^[b] This color scheme originates in the (withdrawn) national standard DIN 47100. The scheme shown here is the correct color code for interfacing with the RJ connector standards.

However, with German domestic telephone equipment (and that in some neighbouring countries), 6P4C plugs and sockets are typically only used to connect the telephone cable to the phone base unit, whereas the mechanically different TAE plug is used at the other end of the cable. Older base units may accommodate the additional connectors of TAE (E, W, a2, b2) and may feature non-RJ standard sockets that can be connected „straight“ to TAE plugs. Further, flat DIN 47100 cables typically place the wires in ascending order. When used directly with 6P4C plugs, the colors will be garbled.

Powered version of RJ11

In the powered version, Pins 2 and 5 (black and yellow) may carry low voltage AC or DC power. While the phone line itself (tip and ring) supplies enough power for most telephone terminals, old telephone terminals with incandescent lights in them (such as the classic Western Electric Princess and Trimline telephones) need more power than the phone line can supply. Typically, the power on Pins 2 and 5 comes from a transformer plugged into a wall near one jack, supplying power to all of the jacks in the house. Trimline and Princess phone dial lights are rated at 6.3 volts and the transformer output is typically around 5 volts, providing a long service life for the incandescent lamps.

Compatibility with Structured Cabling

With the rise of Ethernet local area networks operating over Cat5e and Cat6 unshielded twisted pair cable, structured cabling networks adhering to TIA/EIA-568-B, ISO/IEC 11801 or ISO/IEC 15018 (home networks) are widely used for both computer networking and analog telephony, but these standards specify the T568-A or T568-B pin-outs compatible with Ethernet. The 8P8C ("RJ45") jack used by structured cabling physically accepts the 6-position connector used by RJ11, RJ14 and RJ25, but only RJ11 and RJ14 have full electrical compatibility. Ethernet compatible pin-outs "split" the third pair of RJ25 across two separate cable pairs, rendering it unusable by analog phones. This was necessary to preserve the electrical properties of those pairs for Ethernet, which operates at much higher frequencies than analog telephony.

Both the third and fourth pairs of RJ61 are similarly split. Because of this incompatibility, and because they were never very common to begin with, the TIA/EIA-568-B conventions are displacing RJ25 and RJ61 for telephones with more than two lines.

8P8C

This article is about the generic 8P8C modular connector. For the RJ45 connector used in telephone installations, see RJ45. For the registered jack (RJ) wiring standard, see registered jack.

An 8P8C modular plug before being crimped onto a cable

Connector and cable

The 8P8C (8 Position 8 Contact, also backronymed as 8 position 8 conductor; often called RJ45) is a modular connector commonly used to terminate twisted pair and multiconductor flat cable. These connectors are commonly used for Ethernet over twisted pair, registered jacks and other telephone applications, RS-232 serial using the EIA/TIA 561 and Yost standards, and other applications involving unshielded twisted pair, shielded twisted pair, and multiconductor flat cable.

An 8P8C modular connector has two paired components: the male plug and the female 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 insertion interface. When an 8P8C plug is mated with an 8P8C jack, the conductors meet and create an electrical connection. Spring tension in the jack's conductors ensure a good interface with the plug and allow for slight travel during insertion and removal.

Although commonly referred to as an RJ45 in the context of Ethernet and category 5 cables, it is technically incorrect to refer to a generic 8P8C connector as an RJ45. The registered jack (RJ) standard specifies a different mechanical interface and wiring scheme for a RJ45S than TIA/EIA-568-B which is often used for modular connectors used in Ethernet and telephone applications. 8P8C modular plugs and jacks look very similar to the plugs and jacks used for FCC's registered jack RJ45 variants, although the RJ45S is not compatible with 8P8C modular connectors.

"RJ45" naming confusion

See also: registered jack naming confusion

The RJ45 was originally a connector used for other telephone-only standards. It is a modular connector used in many registered jacks, similar to RJ11, another telephone standard. Registered jacks specify the physical male and female connectors as well as the pin assignments of the wires in a telephone cable. The original RJ45S used a special keyed 8P2C modular connector, with Pins 5 and 4 (the middle 2 positions) wired for tip and ring of a single telephone line and Pins 7 and 8 shorting a programming resistor. It was meant to be used with a high speed modem, and is obsolete today.

Telephone installers who wired RJ45S modem jacks or RJ61X telephone jacks were familiar with the pin assignments that were part of the standard. However, the standard un-keyed modular connectors became ubiquitous for computer networking, and informally inherited the name "RJ45". While RJ45S uses a "keyed" variety of the 8P body, meaning it may have an extra tab that a common modular connector is unable to mate with, the visual difference is subtle and likely caused the confusion.

Understandably, because telephone RJ61 and data RJ45/RJ48 connectors never saw wide usage and computer 8P8C connectors are quite well known today, "RJ45" is used almost exclusively to refer to modular connectors with Ethernet-type wiring pin-outs. Electronics catalogs commonly advertise 8P8C modular connectors as "RJ45", but of course they are commonly installed into generic structured cabling systems such as ISO/IEC 15018 or ISO/IEC 11801 using RJ45 patch panels to interconnect both phone and data. Virtually all electronic equipment using an 8P8C connector (or possibly any 8P connector at all) will document it as an "RJ45" connector. In common usage, RJ45 may also refer to the pin assignments for the attached cable, which are actually defined as T568A and T568B in wiring standards such as TIA/EIA-568-B.

Standardization

The shape and dimensions of an 8P8C modular connector are specified for U.S. telephone applications by the Administrative Council for Terminal Attachment (ACTA) in national standard ANSI/TIA-1096-A. This standard does not use the short term 8P8C and covers more than just 8P8C modular connectors, but the 8P8C modular connector type is the eight position connector type described therein, with eight conductors installed. The international standard is ISO-8877.

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

Wiring

T568A wiring

T568B 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 was needed to interconnect similar network equipment (such as hubs to hubs). A cable wired the same at both ends is called a "patch" or "straight-through" cable, because no pin/pair assignments are swapped. Crossover cables are sometimes still used today to connect two computers together without a switch or hub, however most Network Interface Cards (NIC) in use today are called smart, because they automatically configure themselves based on the type of cable plugged into them. If a "patch" or "straight" cable is used, to connect two computers with "smart" NICs, the NIC will configure itself to switch the Tx and Rx.

Types

Two 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, the tooling used to install the two different plug types is mutually exclusive and cannot be interchanged between the two types. WE/SS compatible plugs are available from a large number of manufacturers, whereas Tyco/AMP plugs are produced exclusively by Tyco Electronics. Both types of modular plugs will plug into the same standard 8P8C modular jack.

WE/SS and Tyco/AMP 8P8C plugs have different spacing for the cable strain relief. As a result, using a WE/SS 8P8C crimp dieset on a Tyco/AMP 8P8C plug will crush the top of the connector, and vice versa. While the WE/SS compatible plug is produced by a larger number of manufacturers than the Tyco/AMP plug, it is still important 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 tolerance needed. Shielded plugs are more expensive and require shielded cable, but have a lower attenuation and can reduce signal noise.

Termination

Termination 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 eight teeth lining the top portion of the die. When the tool is operated, the die compresses around the 8P8C plug. As the die compresses, these teeth force the plug contacts down into the conductors of the cable being terminated, permanently attaching the plug to the cable. There are two sub-types of plug, that differ only in the type of contacts used. One contact suits solid copper cable and the other suits stranded copper cable. The crimper may also permanently deform part of the plug body in such a way that it grips the outer sheath of the cable. This helps to keep the plug securely fastened to the end of the cable, by providing strain relief.

Applications

8P8C are commonly used in computer networking and telephone applications, where the plug on each end is an 8P8C modular plug wired according to a TIA/EIA standard. Most network communications today are carried over Category 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. 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 environments the center (blue) pair is often used to carry telephony signals. Where so wired, the physical 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. The formal 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 this pair; this conflicts with other equipment as manufacturers used to short circuit unused pairs to reduce signal crosstalk. Some routers/bridges/switches can be powered by the unused 4 lines—blues (+) and browns (−)—to carry 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 be linked to wire connectors (often IDC type terminals) that are in a different physical arrangement from that of other manufacturers: Thus, for example, if a technician is in the habit of connecting the white/orange wire to the "bottom right hand" IDC terminal, which links it to 8P8C modular connector pin 1, in jacks made by other manufacturers this terminal may instead connect to 8P8C modular connector pin 2 (or any other pin).

10P10C

The pin arrangement for a 10P10C socket

The 10P10C modular connector is a type of electrical connector.

Terminology

The 10P10C connector is commonly referred to as an RJ50 connector, although this is not a standard registered jack in the Universal Service Order Codes. The 10P10C is a telephone-style connector featuring 10 pins and 10 connection wires.

Common Uses

The most common uses of the 10P10C connector are in proprietary data transfer systems, such as the Digi International Digiboard serial connections. It is also used to implement the RS-232 and RS-485 connector standards. It is also used in APC and Eaton uninterruptible power supplies. In this case, it is a keyed 10P10C plug with a protrusion on the pin 1 side near the back.

This connector is also used by some vendors such as BOCA, for expansion modules of their multi-port RS-232C serial boards. For example, Cyclades used the pin #1 as a "RI" (Ring Indicator) signal, which is rarely used, allowing an 8P8C connector to be plugged to their 10P10C socket for most applications. The Cisco Systems STS-10X terminal server featured this connector. FordNet, a five-pair communications networking medium also used the 10P10C between terminals.

See also

• Telephone plug
• Modified Modular Jack
• registered jack
• Ethernet over twisted pair
• List of registered jacks
• RJ45
• ARJ45
• GG45
• TERA
• BS 6312: British equivalent to RJ25

References

• ANSI/TIA-968-A: Telephone terminal equipment: Technical requirements for connection of terminal equipment to the telephone network
• IEC 60603-7-1: Connectors for electronic equipment: Part 7-1: Detail specification for 8-way, shielded free and fixed connectors with common mating features, with assessed quality
• IEC 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 MHz
• IEC 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 MHz
• IEC 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 MHz
• ISO/IEC 8877, EN 28877: Information Technology—Telecommunications and Information Exchange between Systems—Interface Connector and Contact Assignments for ISDN Basic Access Interface Located at Reference Points S and T
• Registered Jack references are US government documents that define modular connectors for telecommunications. (Note: 4P4C and 10P10C connectors are NOT defined in these standards.)

Further reading

• TIA-968-A
• TIA-1096-A
• UTP cable termination standards 568A vs 568B
• John R. Carlsen: On wiring modular telephone connectors
• Modular jack wiring
• Modular wiring reference showing differences between 8P8C, true RJ45 8-position keyed connector, 6P6C, and 6-position modified offset tab
• Common outlet configurations graphical representation of twisted pair pinouts
• Catalog page showing the difference between solid and stranded contacts
• 8 pin RJ45 connector diagram and applications

External links

• How to Make a Network Cable, a how-to article from wikiHow
• How to create your own Ethernet Cables
• How to wire a 10Base-T or 100Base-T connector with category 5 cable and 8P8C modular connectors
• Step by step instructions on how to punch down category 5e cable to a RJ45