What is RJ11?

RJ11 interface and RJ45 interface are very similar, but only 4 pins (RJ45 for 8 pins). In the computer system, RJ11 is mainly used to connect the modem.

RJ11 usually refers to a 6-position (6-pin) modular jack or plug. There is no international standard for this type of connector and it is mentioned in the Common Integrated Wiring Standard. Also, the name is often used for 4-pin versions of modular connectors, which causes confusion.

In the general integrated cabling standard, there is no separate mention of ‘RJ11’ in the discourse, and all connecting devices must be 8-pin. Therefore the synergy and compatibility of RJ11 and RJ45 are not yet written.

The name RJ stands for Registered Jack and is derived from the Bell System’s USOC (Universal Service Ordering Codes) code. USOC is a series of registered jacks and their wiring methods that were developed by the Bell System to connect a user’s device to the public network. FCC regulations control the application of this purpose.

RJ11 is the common name of the connector developed by Western Electric, abbreviated as rj11 connector. The form factor is defined as a 6-pin connection device. The original name is WExW, where the x stands for ‘active’, contact, or wire punch pin. For example, WE6W has all 6 contacts, numbered 1 to 6, WE4W interface uses only the outermost two contacts (1 and 6) of the 4-pin without, WE2W uses only the middle two pins. For RJ11, the source of information is contradictory, it can be a 2 or 4 pole 6-pin connector. To add to the confusion, RJ11 is not only used to represent a 6-pin connector, it also refers to the 4-pin version.

RJ11 and RJ14, RJ25 for the same series

RJ11 and RJ14, RJ25 for the same series, the same size, are 9.5mm wide, only the number of contacts is different. RJ11 only the middle pair of contacts, can connect a pair of wires, said 6P2C (six posiTIon, two-conductor); RJ14 use the middle four contacts, can connect two pairs of wires, said 6P4C; RJ25 use all six contacts can connect three pairs of wires, said 6P6C. RJ25 uses all 6 contacts, can connect 3 pairs of wires, said 6P6C.

RJ11 and RJ14, RJ25 series of wire sequence and color table

RJ11 will also be used as an interface for RS-232 or 485, the following are 3 examples

Interface for RS-232 or 485

RJ11 is the U.S. standard telephone connector, while the United Kingdom for BS 6312, France for F-010, Germany for TAE connector, basically similar, while Austria is TDO-connector, Poland for WT-4, the difference is very big.

Currently more commonly used RJ connector is RJ45, for ethernet connection, 8P8C, you can connect four pairs of twisted pairs, 12mm wide, wider than the RJ11 series. RJ45 is sometimes used for telephone or RS232 connections, but also some people use it to pass VGA video signals.

There is also an 8P8C connector called RJ61, used to connect twisted pairs, the line sequence is as follows.

8P8C connector called RJ61 wire sequence

Because this line sequence in the 3rd and 4th pair of twisted pairs in the two lines are far apart, it will cause greater crosstalk, not suitable for Ethernet such high-frequency signal transmission.

There is also an RJ48 connector, also 8P8C can be used to connect four pairs of T1 data links, each pair of lines can transmit time-division multiplexing of 23 voice circuits.

Other less common RJ series connectors

  • RJ2MB: 50-pin miniature ribbon connector
  • RJ12C/RJ12W: 6P6C, for one telephone line ahead of the key system
  • RJ13C/RJ13W: 6P4C, for one telephone line behind the key system
  • RJ15C: 3-pin weatherproof, for one telephone line
  • RJ18C/RJ18W: 6P6C, for one telephone line with a make-busy arrangement
  • RJ21X: 50-pin miniature ribbon connector, for up to 25 lines
  • RJ26X: 50-pin miniature ribbon connector, for mulTIple data, lines
  • RJ27X: 50-pin miniature ribbon connector, for mulTIple data lines
  • RJ31X: 8P8C (usually only 4C are used), single line with alarm – center pins #4 & #5 connect to phone line; outside pins #1 & #8 connect to another phone jack allowing the alarm dialer or medical alert system to dial the monitoring company when triggered.
  • RJ38X: 8P8C, similar to RJ31 but a connecTIon between pin #2 & #7 indicates that a plug is inserted.
  • RJ41S: 8P8C keyed, for one data line, universal
  • RJ45S: 8P2C + keyed, for one data line with a programming resistor
  • RJ49C: 8P8C, for ISDN BRI via NT1
  • RJ50: 10P10C, the same size as RJ45 but with ten contacts Business phone
  • RJ71C: 12 line series connection using 50 pin connector


Form: https://www.youtube.com/watch?v=W0KDnF8mQaU

Some Questions:

What is the difference between RJ11 and RJ45?

RJ45 connectors commonly connect to Cat5 and Cat6 cables, while RJ11 simply connects to a telephone cable. RJ45 can connect to various devices in a copper cable network such as switches, cables, computers, routers, and so on. Switches with RJ11 connectors comprise mainly two sockets for a 2-line telephone system.

What devices use RJ11?

Phones, ADSL lines, modem cables. RJ11 is mostly used for voice applications. Computer networking. RJ45 is used in Ethernets or connecting cable modems with Wi-Fi routers.

What are RJ11 ports?

More commonly known as a modem port, phone connector, phone jack, or phone line, the Registered Jack-11 (RJ-11) is a four or six-wire connection for telephone and modem connectors in the US.

Is DSL RJ11?

Description. A DSL router consists of a box with an RJ11 jack to connect to a standard subscriber telephone line. It has several RJ45 jacks for Ethernet cables to connect it to computers or printers, creating a local network.

Is Cat 3 the same as RJ11?

A Cat3 cable is typically thinner and features a smaller RJ11 or RJ24 connector. Cables usually have their specifications printed along the plastic covering at regular intervals to aid easy identification.

What is the RJ11 fax port?

J. R. (Registered Jack-11) A telephone interface that uses a cable of twisted wire pairs and a modular jack with two, four, or six contacts. RJ-11 is the common connector for plugging a telephone into the wall and the handset into the telephone. See modular connector.

Why would you use an RJ11 connector?

RJ11 connectors are typically used for telephones and modems. When would you typically use an RJ11 connector? An RJ11 connector is used for connecting analog telephones to the telephone jacks. Cat 3, Cat 5, and higher twisted pair cables use RJ45 connectors.

How long can you run the RJ11 cable?

RJ11 cable length for the 2-wire analog phone is supported up to 100 meters. It is highly recommended to use a standard 2-wire analog phone without its LCD display.

Can you connect RJ11 to the RJ45 port?

Warning – Don’t plug an RJ11 plug into an RJ45 socket
RJ11 plugs can permanently damage your RJ45 socket. Data cabling systems normally use RJ45 connectors. These have eight pins.

Can we convert RJ45 to RJ11?

There is no such thing as an RJ45 to RJ11 converter. Two different types of connectors for two totally different standards of communication. RJ11 is a standardized jack using a 6P2C (6 positions 2 contacts) modular connector, commonly used for single-line telephone systems.

How do I connect my laptop to my RJ11?

You don’t need an adapter to plug an RJ11 male (2/4/6 connector modular telephone jack) into a RJ45 female port (8 wire modular telephone port). Just plug it in. It just works. Well, it works, if you have telephone signal on the center 2 or 4 wires of the RJ45 jack.

What connectors do telephones use?

There are two types of common modular plugs; the RJ-11 and RJ-14. The most common is the RJ-11, which uses only two of the telephone wires in a four (or more) strand wire. This is the same kind of plug that you use to plug your telephone into the wall: a 1-line plug.

What is difference between RJ11 and RJ12?

RJ11 is an older version of RJ12, and they are the same size. The difference is that RJ11 uses four internal wires (called conductors) while RJ12 uses six. RJ12 is backwards compatible with RJ11, but RJ11 will not work with RJ12.

Does DSL use RJ11 or RJ45?

Verify that your modem is indeed DSL. You should be able to use a standard phone cord, both end with RJ11, and plug that sucker into the WAN port. A RJ11 plug will go into an RJ45 jack, just do it carefully to make sure the skinny plug is CENTERED as you shove it in, must get a solid click.

Does RJ11 cable length affect speed?

While increasing your distance may not affect your speed per say, it can affect the modem’s ability to sync properly with the DSLAM and can cause a lower sync rate, line, CV or HEC errors (either causing slower speeds or a bouncing circuit).