Difference between RJ45 and RJ11.

What is Registered Jack (RJ)?

A Registered Jack (RJ) is a defined telecommunication network interface for connecting voice and data equipment to a local exchange carrier or long-distance carrier's service. The Universal Service Ordering Code (USOC) system of the Bell System in the United States was the first to specify registration interfaces for compliance with the registration program for customer-supplied telephone equipment mandated by the Federal Communications Commission (FCC) in the 1970s.

After Bell Labs invented Registered Jack connections in 1973, they became popular. Physical construction, wiring, and signal semantics are all included in the standard. As a result, registered jacks are commonly referred to by the letters RJ, followed by two numerals indicating the kind. Minor differences are indicated by additional letter suffixes. RJ11, RJ14, and RJ25, for example, are the most widely used interfaces for telephone connections

What is RJ45?

RJ45 is a modern, modular, self-securing, and compact technology that is used to connect Ethernet cables to various electronic devices. RJ45 is an eight-pin connection that connects Ethernet interfaces. RJ45 connectors have eight pins to which a cable's wire strands connect electrically.

Individual wires are placed using specific cable crimping tools into eight places spaced approximately 1 mm apart on each plug. This type of connection is known as an 8P8C connector, which stands for eight positions, eight contacts.

Types of cables based on the termination −

  • Straight-over cable

  • Crossover cable

What is RJ11?

RJ11 is a kind of connector that is used to connect traditional PSTN telephone networks. The RJ11 connection has four pins and is used to terminate telephone lines. The RJ11 uses the center two connections out of the six available for wiring a single phone line. It's the standard connector for connecting a phone to the wall and a handset to the phone.

A 6P2C connection is required for cords that connect to an RJ11 interface. Nonetheless, 6P4C connectors (six-position, four-conductor) with four wires are commonly used in RJ11 cables. The other two conductors are unused, and two of the six potential contact locations link tip and ring.

Difference between RJ45 and RJ11

The following table highlights the major differences between RJ45 and RJ11 −

Key RJ55 RJ11
Usage RJ45 is used with Ethernet cables. RJ11 is used with telephone cables.
Size RJ45 is larger in size. RJ11 is comparatively smaller in size.
Supported Bandwidth Bandwidth up to 10 Gbps over Ethernet is supported. RJ11 supports a maximum bandwidth of 24 Mbps.
Connected wires RJ45 has a total of eight wires attached to it. RJ11 has a total of four wires attached to it.
Connector RJ45 is 8P8C connector. RJ11 is 6P4C connector.


RJ stands for Registered Jack; it is a standardized network interface to connect voice and data communication equipment.

RJ45 is new, modular, self-secured and compact. It uses 8-pin connectors to connect Ethernet connectors and connect Ethernet cables to different electronic devices.

RJ11 is used in conventional PSTN telephone networks. It uses 4 pin connectors to terminate the telephone wires. RJ11 is a common connector to plug a telephone into wall and handset into telephone.