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Why is the Registered Jack divided into RJ45, RJ12 and RJ11?

Time: 2020-10-29


What’s Crystal Head / Registered jack(RJ)?


Registered jack is a standardized telecommunication network interface. Provide interfaces for voice and data transmission. It is a plastic connector that can be inserted in a fixed direction and automatically prevents it from falling off. It is commonly known as "crystal head" and the professional term is RJ-45 connector (RJ-45 is a network interface specification, similar to RJ-11 interface , Is the "telephone interface" we usually use to connect to the telephone line). The reason why it is called "crystal head" is because of its crystal clear appearance. The crystal head is suitable for on-site termination of equipment rooms or horizontal subsystems, and the shell material is high-density polyethylene. The two ends of each twisted pair are connected to the network card and the hub (or switch) by installing a crystal plug.


Do you know what these abbreviations and numbers mean?


The name RJ stands for Registered Jack, which is a standardized network interface. The number at the back represents the serial number of the interface standard, that is, P and C means that the crystal head has several Position grooves and several metal Contact.


What’s The Difference Between RJ45,RJ12 and RJ11?


RJ45 crystal plug is a connector with 8 pins (8P8C), mainly used in Ethernet, "45" means the serial number of the interface standard. RJ45 crystal plugs are usually terminated on an Ethernet cable to connect various network devices, such as computers, routers, switches, etc.


The RJ11 crystal head is similar to the RJ45 crystal head, but only has 4 pins (6P4C), which are often used to connect phones and modems. It should be noted that RJ11 usually refers to a 6-position (6-pin) modular jack or plug, but only 4-pin is used.

Therefore, the volume of RJ45 crystal head is larger than RJ11 crystal head.


RJ12 is a 6P6C connector. It can be used as a telephone line or other voice communication, but it is rarely used by home users.


Do all kinds of RJ connector could be used in Xianglong handset?

We would like to say YES!

Whatever RJ45、RJ11、RJ12、RJ9 etc., Xianglong's handsets can be matched and wired accordingly to meet customers any special requirements.

Welcome to talk with us if you have any questions or demands.