Gigabit Ethernet has become the mainstream in enterprise networks, campus networks, data centers, and broadband access networks. Most gigabit switches are equipped with both RJ45 electrical ports and SFP optical ports. Many users need to interconnect these two ports but do not know the correct method. This article will explain the solution using SFP Copper‑T electrical modules, with industry‑standard applications and cost‑effective guidance.

What Are Gigabit RJ45 Port and SFP Optical Port?

Now Gigabit Ethernet has been popularized in a large area, and Gigabit Ethernet switches are also widely used in scenarios such as enterprise networks and optical access networks. Gigabit Ethernet has two types of ports, namely RJ45 and SFP ports. These two ports can support the highest transmission rate of Gigabit, and can also be backward compatible with the transmission rate of 10/100M.

The RJ45 port is a built-in electrical port of a Gigabit Ethernet switch, and it is mainly connected by Category 5, Category 5e, Category 6, and Category 6e twisted-pair cables. The SFP port is a built-in optical port of a Gigabit Ethernet switch, so it cannot be directly connected with a twisted pair or a jumper. It needs to be connected to an optical module first, and then it can be transmitted with an optical fiber patch cord.

The RJ45 port is for copper cable transmission, while the SFP port is a modular slot that supports optical modules or electrical modules. They cannot be directly connected without a conversion module.

How to Connect Gigabit RJ45 Port and SFP Optical Port?

Next, ETU-LINK will introduce the interconnection method between Gigabit RJ45 port and SFP port.

To connect Gigabit RJ45 port and SFP port, you can use ETU-Link Gigabit electrical port module, specification model: ES-T1-R, it is actually an interface converter, so it is also called optical port to electrical port module. Insert the Gigabit electrical port module into the SFP optical port, and then connect the Category 6 network cable to the Gigabit RJ45 port.

This method realizes SFP optical port to RJ45 electrical port conversion and supports full duplex gigabit transmission. The connection is plug‑and‑play, no configuration required.

What Are the Types of Gigabit SFP Copper-T Electrical Modules?

Gigabit electrical port modules are mainly used in the interconnection between short-distance Gigabit RJ45 ports and SFP ports. Gigabit electrical ports are divided into pure 1000M electrical ports (ES-T1-R) and 10/100/1000M adaptive electrical port modules ( ES-T2-R), the longest transmission distance can reach 100 meters using Category 6 twisted pair.

These modules comply with SFP MSA and IEEE 802.3ab standards, supporting 10/100/1000Mbps rate auto‑negotiation and a maximum transmission distance of 100m over Cat5e/Cat6 UTP cable.

In addition to the Gigabit electrical port module, the electrical port module also has a 10 Gigabit electrical port module, but the twisted pair connected to the 10 Gigabit electrical port needs to be connected with a Category 6 or Category 7 network cable.

10G SFP+ to RJ45 modules support 10GBASE‑T transmission and require Cat6A/Cat7 cables for stable 10G performance up to 30 meters.

What Are the Advantages of SFP Copper-T Electrical Modules?

The above is the method of connecting the Gigabit RJ45 electrical port and the SFP optical port introduced by ETU-LINK. From the perspective of the cost of short-distance transmission, if the switch with the SFP optical port uses an optical module with a patch cord. The cost of transmission will increase, and the use of electrical port modules with six types of twisted pair cables is a low-cost transmission solution.

Copper‑T modules save fiber resources, reduce deployment costs, reuse existing copper cabling, and are ideal for desktop access, cabinet interconnection, and small LAN expansion. They are widely used in Cisco, H3C, Huawei, MikroTik, and other mainstream switches.

Last updated: April 8, 2026