Difference Between RJ9 and RJ12

A registered jack (RJ) is a standard network interface used in network cabling, wiring, and jack design.

The essential capacity of registered jacks is to interface distinctive information hardware and media transmission gadgets with administrations regularly given by phone trades or significant distance transporters.

RJ9 and RJ12 are both crimp gold pin connectors used in telecoms, networking, and even low voltage lighting applications. The difference is determined by the number of contacts on the connector and the actual number of connections.

Since there are more sites, the connector is larger. The specification only defines the cable pattern of a connector, not its sex or geometry.

The name “Jack,” even though the standard doesn’t recognize the sex of the connector, applies to the female connector. These connectors are frequently called “measured connectors.”

They have made the telephone network more particular in the good old days. For the wiring of media communications organizations, the RJ determination is generally indicated.

The RJ standard link-designed connectors are alluded to as RJ connectors and can be utilized in people.

RJ9 vs RJ12

The main difference between RJ9 and RJ12 is that they are utilized for the most part in phone ventures. They have numerous similarities. However, they are recognized by their attributes. There is as of now an immense scope of connectors available, and their highlights are unmistakable. Some are appropriate for telephone and other PC organizing purposes. RJ12 is the most widely recognized, being utilized on level line strings that associate the telephone base to the divider. Coiled handset strings use a more modest connector called RJ9.


The RJ9 has a marginally unexpected shape in comparison to the RJ12. Although it has a rectangular shape, it is smaller than the RJ12.

It’s made of plastic and is transparent because you can see how the wires are connected inside. The RJ9 only has one configuration type, the 4P4C attachment type, which implies four locations and four connection points.

It allows it to work with telephone handset cables.

For a centralized telephone network in offices, RJ12 is a communication jack that connects a central telephone grid with single telephone lines using a line circuit that uses specialized RJ12 6-flat ribbon standard cables.

The RJ12 norm is also used in a variety of other applications. The additional two connectors will be used for keyed telephone systems and PBXs.

As a result, RJ12 is not commonly available, and only those with previous experience dealing with large corporation telecommunications networks are familiar with it.

Comparison Table Between RJ9 and RJ12

Parameters of comparisonRJ9RJ12
Full-FormRegistered Jack 9Registered Jack 12
Connector4P4C = 4 Position 4 Conductor6P6C = 6 Position 6 Conductor
PurposeRJ9 is regularly utilized as cables for telephone handsets.RJ12 is commonly used in system phones.
Physical CharacteristicsRJ9 is rectangular in shape.RJ12 is compact and square-shaped.
DefinitionRj9 is a connector ideal for use in connecting telephone handset cables.RJ12 is a line circuit that associates a focal phone framework to single phone lines through a connection jack

What is RJ9?

There is a ton of disarray around this connector structure. On occasion, it is alluded to as the Rj10, and it might likewise be recognized as the Rj22.

The purpose for this is that every one of these connector types has comparative measurements and designs.

This connector is more rectangular than it is square. It has a width of 7.6mm, making it somewhat more modest than the Rj12 connector. It has a practically comparable form, however.

It is produced using unbending and robust plastic that is additionally clear. This plastic uncovers the association of wires.

This association has a 4P4C arrangement, like that of the Rj10 and Rj22, which explains that they seem similar. Its design implies that it has four positions and four association focuses.

It is ideal for interfacing phone handset links. It has composite pins that are made of copper. The topcoat of these pins is treated with an amalgam of 30 microns of gold and 30 microns of nickel.

It forestalls the copper pins from rusting and gives it an all the more stylishly engaging look.

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What is RJ12?

The full version of Rj12 is Registered Jack 12. It is a jack that links a central telephone grid to individual telephone lines through a line circuit. It’s a male connector that lone joins to a female Rj12 jack to make an association.

A 6P6C connector is used on the Rj12. It has six link slots, with all six slots being used for contact. For Rj12 connectors, specific RJ12 6-level trim standard connections are used.

This link is comprised of six dainty copper links that convey and get electrical messages.

Both six copper wires in this regular ribbon cable are color-coded. White, black, red, green, purple, and blue are the shades used.

The Rj12 is unlike any other wearing device in that it is unique and complicated. To make the copper-wearing device work, the cable technician must put it in the proper order.

When numerous corporate offices needed a consolidated telephone network for private use in the 1980s, the Rj12 connector became common.

This connector makes it simple to set up a phone-based neighborhood in the working environment. Numerous workplaces do go through this connector to set their radio framework, especially in this cutting-edge period.

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Main Differences Between RJ9 and RJ12

  1. RJ9 is rectangular, whereas RJ12 is squared in shape.
  2. RJ9 is used for telephone handset cables, whereas RJ12 is used in the system phones.
  3. RJ9 has a 4P4C connector, whereas RJ12 has a 6P6C connector.
  4. RJ9 is the abbreviation for Registered Jack 9. RJ12, on the other hand, is an abbreviation for Registered Jack 12.
  5. RJ9 is visually pleasing, whereas RJ12 is compact.


The creation of enlisted jack was an upsetting occasion. This jack carried normalization to the telecom business.

Prior to the appearance of the registered jack, parts of each telephone organization were not the same as others. The registered jack set up one norm for all telephone organizations.

Both the RJ9 and RJ12 connectors are highly fundamental in connecting devices and communicating information from sources to devices. They have various qualities and are viable with multiple cables.

They additionally have interesting forms that make it conceivable to see the genuine association of the wires.


  1. https://ieeexplore.ieee.org/abstract/document/6843694/
  2. https://currentprotocols.onlinelibrary.wiley.com/doi/abs/10.1002/cpmo.81
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Last update on 2022-10-01 / Amazon Affiliate links / Images from Amazon Product Advertising API

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