What are the RJ11 RJ12 RJ45 connectors used for ?  What's the difference?

1. The RJ45 crystal head is an 8-pin connector, mainly used for Ethernet, "RJ" indicates a registered jack, and "45" indicates the serial number of the interface standard. The RJ45 crystal head usually connects the end to the Ethernet cable, which is used to connect various network devices, such as computers, routers, switches, etc.

2. The RJ11 header is very similar to the RJ45 header, but only has 4 pins. It is Western Electronics Co. , Ltd. A connector developed, typically used to connect telephones and modems.

It should be noted that RJ11 usually refers to a 6-position (6-pin) modular jack or plug, but only uses 4 pins. In addition, RJ11 is also used in the 4-pin version of the modular connector.

3. RJ12 is a 6-piece connector with 6 positions and 6 conductors that can be used as a telephone line. Although the technology still exists, it seems to have become a mobile technology and many people are moving.

It's important to note that RJ11 and RJ 12 use the same switch, the main difference between the two RJ 11's is using only 4 positions, while all positions use RJ12. The type you can rely on can be a phone or CAT5 cable.
 

4. The RJ45 plug is a connector with 8 grooves and 8 contacts (8p8c), while the RJ11 plug usually has only 6 grooves and 4 contacts (6p4c), so the RJ45 plug is larger, The RJ11 crystal head is bigger.

Usually, you can plug the RJ11 plug into the RJ45 port and vice versa, but it is strongly recommended not to use the RJ11 plug for the RJ45 port.

5. RJS can be used by local service providers or even remote providers. There are several standards for registered jacks, and their nomenclature depends on the wiring. These include RJ11 registered jacks, RJ14, RJ21, RJ48 and RJ45.

The two most commonly used RJs in the world are RJ 12 RJ 45. It is these two registered jacks that can see the difference. It is important to note the connector types used for RJ physical connector modules and mini ribbon connectors.

Stacked RJ45 Connector cable

CAT 5e, Panel Mount, Snap In, RJ45

RJ45 panel mount connector cable

Snap in RJ45 Panel Mount Cable

Stack RJ45 USB Connector Cable

RJ45 USB Combo Connector Panel Mount