Ultimate Introduction to RJ45 Interface

Information is transmitted through cables by properly connecting to an RJ45 interface or RJ45 connector. The cable must be terminated with a connector to facilitate this transmission. Typically, an RJ45 jack is used for this purpose. RJ45 connectors are commonly found on Ethernet network cables, which are also referred to as RJ45 cables. These cables are equipped with a small plastic plug on each end, inserted into the RJ45 jacks of Ethernet devices. If you need clarification on the various types of RJ45 interfaces, continue reading to learn more.

 

What Is RJ45 Interface?

 

The RJ45 interface is widely recognized as the predominant connector for Ethernet cables and networks that utilize twisted-pair wiring.

 

"RJ" stands for "registered jack," which refers to a standardized telecommunication network interface connecting voice and data equipment to services provided by local exchange carriers or long-distance carriers.

 

The number "45" corresponds to the specific interface standard associated with RJ45.

 

 

From a physical perspective, registered jacks primarily employ modular and 50-pin miniature ribbon connectors. The RJ45 connector is an 8-position, 8-contact (8P8C) modular plug and jack commonly used in Ethernet-based local area networks (LANs). The standard RJ45 cable plug typically comprises a plastic connector housing with eight pins on the port. Four of these pins are utilized for sending and receiving data, while the remaining four may be employed for other technologies or powering network devices.

  

The Difference Between RJ45 Connector vs. RJ11 Connector

 

In addition to the RJ45 interface, other connector types, such as the RJ11 interface, can sometimes confuse. The RJ11 connector is typically used for wiring a single phone line and comes in a 6P2C or 6P4C configuration. On the other hand, the RJ45 connector follows an 8P8C configuration. One of the critical differences between RJ45 and RJ11 lies in the number of wires in their connectors. Upon closer examination, you'll notice that the RJ45 connector has eight wires. In comparison, the RJ11 connector has four wires, resulting in the larger size of the RJ45 connector than that of the RJ11 connector.

 

As mentioned earlier, the RJ11 plug, with 2 or 4 of the available six connection points, supports limited-bandwidth applications such as phone lines and ADSL connections. In contrast, the RJ45 connector's eight contacts allow for greater bandwidth. As a result, RJ45 is well-suited for data-intensive applications, notably Ethernet, as it can support bandwidths of up to 10Gbps. In some office setups, RJ45 is also used for VoIP phones.

 

The following table shows the difference between RJ45 vs. RJ11

 

 

It is important to note that RJ45 connectors are incompatible with RJ11 slots and vice versa. Attempting to insert an RJ45 connector into an RJ11 slot or vice versa will not work and can potentially damage the equipment designed for the specific slot type. While the RJ11 connector may be smaller, it should not be inserted into an RJ45 port as it is not designed for that purpose and can lead to equipment damage. It is crucial to ensure compatibility and use the appropriate connectors for each slot type to avoid damage.

 

How to Identify the RJ45 Interface Color Code?

 

Two commonly used wiring schemes for terminating twisted-pair cables onto RJ45 connectors are T568A and T568B. These standards determine how the eight wires are arranged when connecting the RJ45 connector to a cable. Each wiring scheme has its specific color convention to ensure electrical compatibility. The T568B wiring scheme is generally more widely used. 

 

The figure below shows the differences in color conventions between T568A and T568B.

 

 

Two standards determine the connectivity form of patch cords: straight-through and crossover connections. A straight-through connection occurs when both ends of the patch cords are wired based on the same standard. On the other hand, a crossover connection is established when the ends are wired differently. In specific networking applications, a crossover Ethernet cable is required. This cable type features a T-568A connector on one end and a T-568B connector on the other. It is commonly used for direct computer-to-computer connections without a router, hub, or switch.

 

Different Types of RJ45 Cable

 

RJ45 Ethernet cables refer to cables that have RJ45 connectors on both ends. These cables, such as Cat5, Cat6, and Cat7, are widely utilized for network connections in modern networks. The following part will introduce the common RJ45 cable types.

 

Cat5 vs Cat5e

 

Originally designed to operate at 100 MHz frequencies with a rated cable speed of 100 Mbit/s, Category 5 (Cat5) cables utilize two twisted pairs (four contacts) and can span up to 100 meters. However, as technology advanced, a new specification called Cat5e was introduced, which enforced tighter standards. The Cat5e standard mandated that new cables include all four twisted pairs.

 

While Cat5 and Cat5e patch cables are capable of transmitting Gigabit Ethernet speeds over short distances, assuming they have all four pairs and operate under ideal signal conditions, Gigabit Ethernet employs an optimized encoding scheme tailored explicitly for operation within these lower signal tolerances.

 

Cat6 vs Cat6a

 

Cat6 patch cables, which are backward compatible with Cat5e, adhere to stringent standards and feature enhanced shielding. Designed as the standard for Gigabit Ethernet, Cat6 cables were created as the standard for Gigabit Ethernet, capable of delivering speeds up to 1000 Mbit/s natively, operating at a frequency of 250 MHz. To support 10 Gigabit Ethernet, the maximum cable distance is reduced from 100 meters to 55 meters.

 

Cat6a patch cables further elevate performance by doubling the frequency to 500 MHz and incorporating grounded foil shielding to mitigate noise interference. These improvements eliminate the distance limitation when operating in 10 Gigabit Ethernet scenarios.

 

Category 7 

 

Cat7 patch cable was developed to accommodate the high speeds of 10 Gigabit Ethernet, operating at frequencies up to 600 MHz. In addition to the shielding in Cat6e, Cat7 introduces individual shielding for each of the four twisted pairs. It maintains backward compatibility with Cat5 and Cat6 and supports a maximum distance of 100 meters. Cat7a surpasses previous standards by increasing the frequencies to 1000 MHz, offering an advanced specification that can support forthcoming 40/100 Gigabit Ethernet speeds. The higher frequency also enables the transmission of lower-frequency Cable TV streams.

 

Conclusion

 

RJ45 connectors are vital in establishing Ethernet connectivity for voice and data transmission. They were designed as more compact and cost-effective alternatives to traditional hardwired telephone installations. The convenient plug-and-play nature of RJ45 connectors simplifies the installation process. Compared to RJ11 connectors, RJ45 connectors find broader applications in areas such as Ethernet networking, telecommunications, factory automation, and more. They are commonly used in various networking devices, including Ethernet cables, modems, computers, laptops, printers, and more.