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RJ11 vs. RJ45: What's the Difference?

Edited by Aimie Carlson || By Harlon Moss || Published on January 3, 2024
RJ11 is a 6-position 4-conductor (6P4C) connector primarily used for telephone wiring. RJ45 is an 8-position 8-conductor (8P8C) connector used for network cabling.

Key Differences

RJ11 connectors are smaller with 6 positions and 4 conductors, typically used in telephone wiring, while RJ45 connectors are larger with 8 positions and 8 conductors, predominantly used in network environments for Ethernet connections.
The RJ11 is designed for voice communication and is commonly found in residential telephone connections, whereas RJ45 is designed for data transmission, handling higher bandwidths used in computer networks.
RJ11 connectors are often used in simpler and less demanding applications such as landline telephone services or DSL lines, in contrast, RJ45 connectors are more complex and used in networking for connecting computers, routers, and switches.
In terms of physical appearance, RJ11 connectors are narrower and can fit into RJ45 ports, but RJ45 connectors cannot fit into RJ11 ports due to their larger size.
RJ11 and RJ45 connectors also differ in durability and design, with RJ45 connectors typically being more robust and secure due to their usage in network infrastructure, which requires stability and higher data rates.

Comparison Chart

Size and Conductors

6-position 4-conductor (6P4C)
8-position 8-conductor (8P8C)

Primary Use

Telephone wiring
Network cabling (Ethernet)

Bandwidth and Data Rate

Lower bandwidth, voice data
Higher bandwidth, data transmission

Physical Appearance

Narrower, smaller
Wider, larger

Durability and Design

Less robust, simpler design
More robust, secure design

RJ11 and RJ45 Definitions


RJ11 is a telephone interface connector.
My landline phone plugs into the wall using an RJ11 connector.


An 8P8C connector for high-speed internet connections.
Gigabit Ethernet requires quality RJ45 connectors for optimal speed.


A small, narrow connector for telephony.
I replaced the RJ11 cable to fix the static on my phone line.


A robust connector for secure network infrastructure.
For our office network, all the wall jacks have RJ45 ports.


Standard connector for residential telephone lines.
You'll need an RJ11 jack to install a home phone.


RJ45 is a standard network cable connector.
Ethernet cables are terminated with RJ45 connectors.


A connector for basic voice communication.
DSL modems often use RJ11 for the phone line connection.


A connector used for Ethernet and data transmission.
To set up a wired network, you need RJ45 ports on your router.


A 6P4C connector used in less demanding applications.
Fax machines typically use an RJ11 connector.


Standard for wired network communication.
We use RJ45 cables to connect our computers to the network switch.


Can RJ45 fit into RJ11 ports?

No, RJ45 cannot fit into RJ11 ports due to size differences.

What is RJ11 used for?

Primarily used for telephone wiring.

Can RJ11 fit into RJ45 ports?

Yes, RJ11 can physically fit into RJ45 ports.

Is RJ11 suitable for internet connections?

RJ11 is used for DSL internet but not for high-speed Ethernet.

What is RJ45 used for?

Used for Ethernet and network cabling.

Can RJ11 be used for Ethernet?

RJ11 is not suitable for Ethernet connections.

Can RJ45 be used for DSL?

RJ45 is not designed for DSL connections.

What devices use RJ11?

Devices like telephones and fax machines.

How many wires does RJ45 use?

RJ45 uses 8 wires.

Are RJ11 and RJ45 interchangeable?

They are not interchangeable due to different uses and sizes.

How many wires does RJ11 use?

RJ11 typically uses 4 wires.

Are RJ11 connectors easy to install?

Yes, they are relatively simple to install.

Does RJ45 support high-speed data?

Yes, it's designed for high-speed data transmission.

Is RJ11 still widely used?

Yes, in telephony and DSL connections.

Is RJ45 suitable for telephones?

RJ45 is not typically used for telephone connections.

What devices use RJ45?

Devices like computers, routers, and network switches.

Does RJ11 support high-speed data?

No, it's limited in data transmission speed.

Do RJ11 and RJ45 look similar?

They have a similar style but differ in size and pin count.

Is RJ45 common in modern networks?

Yes, it's standard in modern Ethernet networks.

Are RJ45 connectors easy to install?

They require more precision but are manageable.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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