News Center

Ethernet vs. Phone Cables – What's the main difference?

The main difference between the two is the size of the plastic connector at the end of the cable. Telephones use RJ11/RJ12 connectors, while Ethernet uses RJ45. RJ11/RJ12 only use 4-6 pins, while RJ45 uses 8 pins.



Cat8 Shielded Ethernet Patch Cable


RJ45 Straight/Right 45° Angle Cable



Modular Connector



Both Ethernet and telephone cables are made using modular connectors. These connectors are designed for use with registered jack (RJ) twisted pair cables. The original modular jack was invented by AT&T in the 1960s and used in some phones. Over time, they became popular and eventually became the industry standard in the 1970s.



Each type of modular connector has an RJ designation, but can also be called "#P#C". The first number is the number of metal pins (P) inside the connector. The second number is how many of those pins are actually connected to the wire. The connected pins are called contacts (C). Modern phones use RJ11 (6P4C) or RJ12 (6P6C). Having more wires within a telephone line allows more signal pairs to run through one cable, e.g. a telephone and a fax machine are both connected on one wire. The extra amount of wires in the newer RJ12 also makes it backward compatible with RJ11 (on the other hand, RJ11 is not forward compatible with RJ12).



Because data signals are more complex than telephone signals, these old-style jacks didn't make it to the Internet once the World Wide Web was invented. RJ45 (8P8C) was developed for this purpose and uses four pairs of wires. RJ45 connectors are physically larger than RJ11/RJ12 due to the need for an extra pair of wires. While there are several different types of Ethernet available, they all use RJ45 connectors in their construction. Checking the dimensions and counting the number of pins in the connector is the easiest way to tell if the cable is an ethernet or a phone cable.




6 Pin Telephone Splitter Converter Cable




Whether you need Ethernet cables, phone cords, or any type of cable accessories, Premier Cables are here to help. With thousands of cables in stock and OEM is accepted.

Have questions about Ethernet, phone cables, or any of our other products? You can leave your messages or by email at

Related News

What is a terminal block used for?

While there are many factors to consider when designing an overall system, terminal blocks are an optimal solution for complex electrical system connections. With a variety of color options and configurations, Premier Cable’ terminal blocks offer a range of options to meet your design challenges.

CANBus Applications

CAN-bus has been widely used in various automation control systems. For example, CAN-bus has incomparable advantages in various fields such as automotive electronics, automatic control, smart buildings, power systems, and security monitoring.

Introduction to M12 connector pin coding

M12 encoding types are A encoding, B encoding, D encoding and X encoding. A-code, B-code and X-code are some of the earliest developed and longest-available M12 connectors. The latest M12 coding types currently under development are K coding for AC and L coding for PROFINET DC.

Cables – What are the correct cable sizes for an NMEA 2000 network?

The three different sizes of NMEA 2000 certified DeviceNet standard cabling are "micro," "mid," and "mini."

What are the advantages of NMEA 2000?

The Premier Cable Starter Kits provide everything you need to get to create a basic NMEA 2000 network from scratch.

The role of DeviceNet terminal resistor

DeviceNet_network is a fieldbus network protocol based on Controller Area Network (CAN). In the DeviceNet network, the terminal resistor plays the role of compensation and protection for signal transmission. The function of the terminal resistor is to eliminate signal reflection and interference and ensure the signal transmission quality.