1. What Is an RJ45 Connector?
An RJ45 connector is a standardized interface used primarily for Ethernet networking. It is an 8-position, 8-contact (8P8C) modular connector that terminates twisted-pair copper cables, such as Cat5e, Cat6, or Cat6A. These connectors form the physical link between network devices—computers, switches, routers, and IP cameras—enabling high-speed data communication.
The “RJ” in RJ45 stands for “Registered Jack,” originally defined by the U.S. Federal Communications Commission (FCC). Over time, it has become the universal connector for Ethernet LAN applications across industries.
2. RJ45 Connector Structure and Pinout
Each RJ45 connector contains eight gold-plated contacts that ensure reliable electrical performance and corrosion resistance. The pinout configuration follows either the T568A or T568B wiring standard, which defines how color-coded wires are terminated inside the connector.
Pin Number | Wire Color (T568B) | Function |
|---|---|---|
1 | White/Orange | Transmit + (TX+) |
2 | Orange | Transmit – (TX–) |
3 | White/Green | Receive + (RX+) |
6 | Green | Receive – (RX–) |
4,5,7,8 | Blue, White/Blue, Brown, White/Brown | Used for PoE or reserved |
For Power over Ethernet (PoE) applications (IEEE 802.3af / 802.3at / 802.3bt), additional pins carry DC power alongside data signals, enabling devices like VoIP phones, IP cameras, and access points to operate without external power supplies.
3. Types of RJ45 Connectors
RJ45 connectors are available in multiple designs and materials to suit various environments and network speeds:
a. Shielded vs. Unshielded (STP vs. UTP)
Shielded RJ45 connectors (STP) provide EMI/RFI protection, ideal for industrial or data center environments.
Unshielded RJ45 connectors (UTP) are commonly used in office networks and standard Ethernet cabling.
b. Through-Hole, SMT, and Integrated Magnetics
Modern connectors often integrate transformers, LEDs, and EMI filters within the jack, simplifying PCB design and improving performance.
LINK-PP, for example, provides integrated RJ45 magnetic connectors such as LPJK9036AHNL and LPJK9492AHNL for 10G Ethernet standards.
c. Vertical and Right-Angle Configurations
Depending on PCB layout, RJ45 jacks are available in top-entry (vertical) or side-entry (right-angle) orientations to optimize mechanical design.
d. Single-Port and Multi-Port Modules
Single-port RJ45 connectors are standard for simple devices, while dual-port or stacked connectors are used in switches, routers, and industrial boards to save PCB space.
4. Applications of RJ45 Connectors
RJ45 connectors are ubiquitous across industries due to their versatility and reliability:
Enterprise Networks: Office PCs, VoIP phones, and servers.
Industrial Automation: PLCs, sensors, and control systems.
Telecommunications: Base stations, modems, and gateways.
IoT and Smart Devices: Smart cameras, access points, and PoE lighting systems.
The connector’s proven design ensures signal integrity, low crosstalk, and high durability even in demanding conditions.
5. RJ45 in PoE and Gigabit Networks
As Ethernet standards have evolved, so has the role of the RJ45 connector. It now supports up to 10 Gbps data rates and delivers up to 90W of power through IEEE 802.3bt (PoE++) technology.
To meet these performance demands, manufacturers like LINK-PP engineer RJ45 connectors with integrated transformers and enhanced PCB isolation—ensuring compliance with IEEE Ethernet and PoE standards.
6. Choosing the Right RJ45 Connector
When selecting an RJ45 connector, engineers should consider:
Data rate support (10/100/1000 Mbps or 10G)
PoE compatibility (802.3af / at / bt)
Shielding type (STP/UTP)
Mounting style (THT, SMT)
Environmental sealing and durability
LINK-PP offers a broad portfolio of RJ45 connectors, including PoE-compatible, industrial-grade, and high-speed magnetics-integrated jacks, designed for compatibility with leading brands such as Tyco, TE Connectivity, and XFMRS.
👉 Explore LINK-PP’s full range of RJ45 Connectors engineered for Ethernet, PoE, and Gigabit applications.
7. Conclusion
The RJ45 connector remains the universal interface powering Ethernet connectivity across the globe. Its evolution—from simple LAN applications to high-speed PoE-enabled smart networks—reflects the growing demand for reliable, compact, and high-performance interconnects.
With decades of expertise, LINK-PP provides custom RJ45 solutions that meet modern networking standards—ensuring stable performance, signal integrity, and global compatibility.
