What Is a RJ11 Socket?

The RJ11 interface is very similar to the RJ45 interface, but only has 4 pins (RJ45 has 8 pins). In computer systems, RJ11 is mainly used to connect modem modems.

RJ11

RJ11 interface and

RJ11 usually refers to a 6-position (6-pin) modular jack or plug. This connector has no international standard and is universal

RJ definition and meaning

In the general integrated wiring standard, there is no separate mention of the 'RJ11' discussion, all connected devices must be 8-pin. Therefore, the collaborative work and compatibility of RJ11 and RJ45 have not yet been documented.

The name RJ stands for Registered Jack, which is a USOC (Universal Service Ordering Codes) code derived from the Bell system. The USOC is a series of registered jacks and their wiring methods developed by Bell Systems to connect users' devices to public networks. FCC regulations control applications for this purpose. The FCC (Federal Communications Commission) has issued a document on behalf of the US government that specifies RJ11.

RJ11 is a generic name for connectors developed by Western Electric Co. Its outline is defined as a 6-pin connection device. Originally called WExW, where x means 'active', contact or threading needle. For example, WE6W has all 6 contacts, numbered 1 to 6, WE4W interface only uses the two outermost contacts (1 and 6) of 4-pin. Not used, WE2W only uses the middle two pins. For RJ11, the source of the information is contradictory, it can be a 2-pin or 4-pin 6-pin connector. Even more confusing is that RJ11 is not only used to represent a 6-pin connector, it also refers to a 4-pin version.

Difference between RJ45 and RJ11

Different standards, different sizes (RJ11 has 6P6C \ 6P4C \ 4P4C \ 4P2C, where C represents the number of gold pins of the crystal head; RJ45 has 8P8C)

Due to the different size of the two (RJ11 is 4 or 6 pin, RJ45 is 8 pin connection device), obviously the RJ45 plug cannot be inserted into the RJ11 jack. The reverse is physically feasible (the RJ11 plug is smaller than the RJ45 jack), which makes people mistakenly believe that the two should or can work together. This is actually not the case. It is strongly recommended not to use RJ11 plugs for RJ45 jacks.

Because RJ11 is not internationally standardized, its dimensions, insertion strength, insertion angle, etc. do not conform to international standard connector design requirements, so interoperability cannot be guaranteed. They even cause damage to both. Since the RJ11 plug is smaller than the RJ45 jack, the plastic parts on both sides of the plug will damage the metal pins of the inserted jack.