RJ12 vs RJ45: Difference and Comparison

The rj12 and rj45 are made of plastic material used for a connector. Cable and connectors play a tremendous part in our lives.

We may keep jumping on our television occasionally, and if we do not have a connector to connect cable with it, there is less left to enjoy at home on a joyful Sunday.

RJ is the short form of Registered Jack that allows telecommunications connections with their standardized physical networking interface.

Both these connectors have modular connectors with a mini ribbon connector type. Both these connectors are used for different purposes with different applications.

Key Takeaways

  1. RJ12 and RJ45 are both connectors used in telecommunications and computer networking.
  2. RJ12 has six pins and is used for connecting telephone lines, while RJ45 has eight pins and is used for Ethernet connections.
  3. RJ45 is more commonly used than RJ12, as it supports faster data transfer rates and is compatible with a wider range of devices.

RJ12 vs RJ45

RJ12 or registered jack 12 uses a 6P6C configuration which can connect up to 6 wires simultaneously. It is a compact-shaped device that is used to establish a single telephone connection. RJ45 is large and bulky and used in Ethernet networks that have a configuration of 8P8C. It can support 10 GBPS speed over Ethernet networks.

RJ12 vs RJ45

The rj12 is a connector with six slots of conductors and positioning used to connect phone lines. Even though this technology is still in place, it seems to be pushed out of business due to the increased use of mobile technology in developing nations. But apart from telecommunications, there are many larger places where the rj12 is used as a connector.

The rj45 is a connector with eight slots of conductors and positioning, used to connect large functioning networks. Each conductor in the rj45 varies with their different performance. The rj45 provides extra jabs for connecting with other connectors. It has the wiring of cat 5 and cat 6 wirings used. The rj45 can be easily wired to any kind of pin available out or even in any generic version structured cabling system.

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Comparison Table

Parameters of comparisonRJ12RJ45
Physical characterThe appearance of the rj12 is in a long rectangular shape.The appearance of the rj45 is a squarish shape.
ConfigurationThe rj12 has a 6 position and 6 connector configuration type connecting the cables.The rj45 has an 8 position and an 8 connector configuration connecting the cables.
FunctionThe rj12 helps to connect many telecommunications to one line of the telephone for transmitting data.The rj2 helps to connect large computers and Ethernet networking communications for transmitting data.
Transmission propertyIt cannot deliver heavy transmissions.It can deliver heavy transmissions.
Wiring usedThe rj12 uses cat 3 as well as cat 5 types of wiring.The rj45 uses cat 5 as well as cat 6 types of wiring.
Ribbon connectionThe rj12 has specialized flattened ribbon cable connections made of copper.The rj45 does not have any specialized ribbon connection as such.
Signals transmittedThey help in the transmission of data through analogue signals.They help in the transmission of data through digital signals.
sizeThe rj12 is about 9.65 millimetres long.The rj45 is about 11.65 millimetres long.

What is RJ12?

The connector rj12 is a jack connector that connects a central telephone system with a single telephone line through a circuit line. It’s called a 6p 6c connector.

These six slots of the rj12 are used for the connection and communication of the wires. The rj12 has specialized flattened ribbon cable connections.

This cable consists of six flat cables made of copper and transmits and receives the signals electrically through it. These ribbons are coded using different colours, including red, blue, green, yellow, black, and white.

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These are mainly used to connect the cat three and cat five wirings.

The rj12 has a build that holds it strong from the inside and out. It has a gold coat with copper pins attached to them.

The only drawback of the rj12 connector is that it cannot handle excessively heavy data transmissions.


What is RJ45?

The connector rj45 is used for Ethernet networking commonly. It looks almost like a telephone jack but with a wider surface.

Most of the time, all Ethernet cables are referred to as rj45 cables as the rj45 connectors are used to connect the wire cables. It consists of eight pins. That is, they have 8 different wires.

A person can observe this if he closely looks at any Ethernet cable. Four of these eight wires have solid colours, and the other four are stripped.

This is mainly used to connect Cat 5 and Cat 6 cables. The connector rj45 can hold around eight wires at once, making it have a durable and robust build from the inside and out.

It has copper pins with a gold coating to prevent the wire from rusting due to exterior forces. The main feature of the rj45 connector is that it can transmit very high energy at a very high speed.


Main Differences Between RJ12 and RJ45

  1. The rj12 connector is rectangular, whereas the rj45 connector is square.
  2. The rj12 is a connector with six connectors and six positions, whereas the rj45 is a connector with eight connections and eight positions.
  3.  The rj12 is mainly used for connecting telephone lines, whereas the rj45 is mainly used for wiring many networks.
  4.  The rj12 uses Cat 3 or a Cat five type of wiring, whereas the rj45 uses Cat 5 or Cat 6 for connecting the major lines.
  5.  The rj12 is a six-slot-type connector, whereas the rj45 is an eight-slot-type connector.
Difference Between RJ12 and RJ45
  1. http://support.itx.bg/ASROCK%20IPC/Jumper/IMB-370-L.pdf
  2. https://ieeexplore.ieee.org/abstract/document/8284683/

Last Updated : 13 July, 2023

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27 thoughts on “RJ12 vs RJ45: Difference and Comparison”

  1. The comparison table is very helpful in highlighting the specific differences between RJ12 and RJ45 connectors, making it a valuable reference.

    • Absolutely, Martin. It’s a great resource for those seeking a quick summary of the connectors’ features and functions.

    • Indeed, the table simplifies the complex technical details, making it easier to grasp the disparities between the two connectors.

  2. The post does a great job of outlining the physical characteristics, configuration, and functions of both RJ12 and RJ45 connectors. Well done!

  3. The author effectively describes the construction and wiring properties of both RJ12 and RJ45 connectors, offering valuable insights into their physical characteristics.

  4. The post does an excellent job of explaining the transmission and wiring properties of RJ12 and RJ45 connectors, enriching our understanding of their operational differences.

  5. The post is a bit too technical in its description of RJ12 and RJ45 connectors, making it less accessible to readers without a strong technical background.

  6. This article misses pertinent details, such as specific use cases in different networking scenarios. It’s not as comprehensive as it’s presented.

  7. This seems like basic information that most people would already know about. It would be more helpful to delve into more complex aspects of networking technology.

  8. While the post covers the basics of RJ12 and RJ45 connectors, it lacks a critical analysis of the technological advancements driving their use.

  9. This article provides a comprehensive comparison between the RJ12 and RJ45 connectors and explains their differences thoroughly. It’s very insightful!

    • I completely agree, Isobel! The post does a great job of breaking down the differences between the two connectors in an easy-to-understand manner.


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