Types of Copper cables and optic cables
May 11, 2023
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Nowadays, with the emergence of new businesses such as cloud computing and artificial intelligence, the scale of data centers is continuously expanding, and their architecture and cabling are becoming more complex. The lightweight and gradually decreasing cost of optical fibers has led to a growing demand for fiber optics in backbone network devices. In large data centers, fiber optics account for over 70% of the total cabling, far surpassing copper cables. However, does this mean that fiber optics will completely replace copper cables? Not necessarily.
I. Why is copper cable still an indispensable part of data centers?
1. Application Comparison
Although fiber optics have gained a significant share in data centers, especially in backbone applications, due to the increasing demand for higher bandwidth, copper cables still play an essential role in data centers. In particular, in applications such as voice transmission and power supply in special environments, copper cables cannot be replaced by fiber optics.
2. Unique advantages of copper cables
For comprehensive horizontal cabling within 100 meters, copper cables have advantages over fiber optics in terms of maintenance, cost, and cabling. The fiber cores in optical fibers are fragile compared to copper in copper cables, and without proper attention during installation and maintenance, optical fibers can easily break, resulting in increased costs. Moreover, although the price of optical fibers has decreased to some extent in the market, it is still generally higher than that of copper cables. Therefore, compared to fiber optics, copper cables are more convenient in terms of cabling and maintenance, and they have lower costs.
Copper cables cannot be replaced by fiber optics in applications such as voice signal transmission, wireless access, and power supply systems based on Power over Ethernet (PoE).
Firstly, unlike fiber optics, copper cables transmit data using electrical pulses, making them capable of supporting voice signals. Secondly, copper in copper cables can conduct electricity, while the glass fibers used in optical fibers cannot. As a result, copper cables can simultaneously provide data connectivity and power supply, making them widely used in wireless access, PoE systems, LED-based power systems, and more.
In addition, the TIA-568.2-D standard has approved Modular Plug Terminated Links (MPTL) as an option for connecting devices, which will promote the growth of RJ45 copper cable applications, especially in surveillance systems using IP cameras. Furthermore, the appendix of this specification has introduced 28AWG network patch cords, and smaller-gauge copper cables will help with air circulation and space utilization, enabling their development in high-density applications.
II. What are the types and applications of copper cables?
What are the common types of copper cables? Nowadays, there are various types of copper cables available on the market, such as Category 5e, 6, 6a, 7, and 8 network patch cords. Different types of copper cables have different cabling applications, as follows:
1. Category 5e cable
Category 5e network patch cords, also known as Cat5e cables, were developed by TIA/EIA in 2001. They have low attenuation, minimal crosstalk, a maximum bandwidth of 100MHz, and a maximum transmission rate of 1000Mb/s. Compared to Category 5 cables, Cat5e cables offer significant performance improvements, including higher attenuation-to-crosstalk ratio (ACR), signal-to-noise ratio (SNR), and smaller delay errors. Cat5e network patch cords are suitable for 100Mb/s and 1000Mb/s Ethernet, commonly found in home networks or indoor cabling. Generally, the maximum transmission distance of Cat5e cables does not exceed 100 meters, with the ideal distance being within 90 meters.
2. Category 6 Cable
Category 6 network patch cords, also known as Cat6 cables, have a bandwidth of 250MHz and a maximum transmission rate of 10Gb/s. Compared to Category 5e cables, the internal structure of Cat6 cables is optimized. They utilize a cross-skeleton structure with a smaller twisted pair pitch, which improves performance in terms of crosstalk and return loss. Cat6 cables offer higher transmission performance than Category 5e cables and are more suitable for applications with transmission rates exceeding 1Gbps. Generally, the maximum transmission distance for Cat6 cables does not exceed 100 meters.
3. Category 6a Cable
Category 6a network patch cords, also known as Cat6a cables, are an improved version of Cat6 cables. They have twice the bandwidth of Cat6 cables, with a transmission frequency of up to 500MHz and a maximum transmission rate of 10Gb/s. Due to the superior structure of Cat6a cables, they help eliminate alien crosstalk (AXT) and can support distances of up to 120 meters, although it is recommended to stay within 100 meters for practical applications. Additionally, Cat6a cables have thicker conductor materials compared to Cat6 cables, making them more suitable for industrial environments.
Many people in the low-voltage field may have questions about the differences between Cat6 and Cat6a cables. The following diagram provides a comparison to help illustrate the differences.
4. Category 7 Cable
Category 7 network patch cords, also known as Cat7 cables, have a transmission frequency of up to 600 MHz and support 10Gbps transmission rates within a transmission distance of 100 meters. They are suitable for 10 Gigabit Ethernet. Compared to previous generations of network patch cords, Cat7 cables have strong shielding capabilities, effectively reducing attenuation. They are suitable for connecting switches, patch panels, and other equipment in high-density data centers. It's worth mentioning that at a transmission distance of 50 meters, Cat7 cables can achieve transmission rates of up to 40Gbps, and even at a distance of 15 meters, the rate can reach 100Gbps. Currently, Cat7 cables have not been widely adopted due to their lack of flexibility and manageability.
5. Category 8 Cable
Category 8 network patch cords, also known as Cat8 cables, are the next-generation twisted-pair copper cable standard defined by ANSI/TIA-568-C.2-1. They support a bandwidth of up to 2000MHz and a transmission rate of up to 40Gb/s. However, their maximum transmission distance is only 30 meters, making them suitable for short-distance connections in data centers, such as servers, switches, and patch panels. Cat8 cables are designed specifically for 25GBASE-T and 40GBASE-T applications, making them particularly suitable for interconnecting data center switches and servers.
Ⅲ. Summary
Fiber optic cables and copper wires are two common transmission media in data centers. Both offer resistance to interference and good security. But what are the key differences between fiber optics and copper wires? The differences mainly lie in the following four aspects:
1. Transmission Distance
Generally, the transmission distance of copper wires does not exceed 100 meters, while the maximum transmission distance of fiber optics can reach up to 100 kilometers (single-mode fiber), far surpassing that of copper wires.
2. Transmission Speed
Currently, the maximum transmission speed of copper wires can reach up to 40 Gbps (like Category 8 Ethernet cables and DAC passive copper cables), whereas fiber optics can achieve speeds up to 100 Gbps (such as OM4 fiber optic patch cords), significantly outpacing copper wires.
3. Maintenance and Management
Creating rj45 plugs and connecting device ports with copper wires is relatively simple. In contrast, cutting, splicing, and connecting fiber optics require higher precision and are more complex operations.
4. Cost
For the same length, fiber optics are generally slightly cheaper than copper wires. However, the cost of fiber optic connection equipment (such as fiber optic couplers) and installation is higher than that of copper wires. Therefore, in terms of project costs, fiber optics tend to be more expensive than copper wires.
From the above comparison, it is clear that both fiber optics and copper wires have their own advantages.
Copper cables still hold significant importance in applications such as voice transmission, indoor networks, horizontal cabling, and POE systems. They will not be completely replaced by fiber optics. Moreover, copper technology is continuously being researched and developed to meet future demands for connecting more devices.
