Why is the RJ45 not many contacts but the bandwidth is large?USB2 has 4 contacts, USB3 has 9, and full blood TypeC has 24, but RJ45 only has 8. Why does it not have many contacts but can achieve a large bandwidth?(RJ45 I have heard of 40Gbps so far, which is about the same as the latest USB4 bandwidth).RJ45, as a widely used network interface, has a relatively small number of contacts but a large bandwidth, and the main reason for its design principle and the protocol used. The RJ45 interface consists of a plug (often referred to as a "crystal head") and a socket (often referred to as a "module") with 8 grooves and 8 contacts on the plug. These contacts are primarily used for data transmission and are available as unshielded twisted pair (UTP) or shielded twisted pair (STP) connections.
The RJ45 can reach very high levels of bandwidth, such as 40Gbps, mainly because it uses the Fibre Channel protocol. The Fibre Channel protocol is a high-speed networking protocol capable of delivering transmission speeds of up to 10Gbps over copper cables. In addition, it has been reported that the maximum bandwidth of the RJ45 interface can reach 100Gbps.
In contrast, the bandwidth of a USB interface depends mainly on its version and purpose. For example, USB20 has 4 contacts, USB30 has 9 contacts, while USB40 (also known as USB4 40Gbps) can reach speeds of up to 40Gbps. However, it is worth noting that USB40 and Thunderbolt 4 are two different standards, where Thunderbolt 4 is a specification certification based on USB4.
The data transfer rate of the Type-C interface can also reach very high, such as 80Gbps. The Ethernet protocol supports a variety of rates, including 10Mbps, 100Mbps, 1Gbps, 10Gbps, etc., among which 10Gbps Ethernet has become the mainstream high-speed network interface standard. The RJ45 interface supports a wide range of Ethernet rates, and its bandwidth can be increased by increasing the signal transmission rate and increasing the number of signal lines.
RJ45 has a small number of contacts but a large bandwidth, mainly due to the different protocols and signal transmission methods used by USB. The RJ45 interface is a type of Ethernet interface, which uses the Ethernet protocol, which is a LAN protocol based on a bus-type topology. The Ethernet protocol uses a differential signal transmission mode, that is, data is transmitted through a pair of signal lines (plus or minus two wires), which can effectively reduce signal interference and attenuation, and improve the quality and speed of signal transmission.
The 8 pins of the RJ45 interface are used for transmitting data, sending and receiving signals, and supplying power. The number pin is used to transmit data, the number pin is used to receive data, the number pin is used to transmit differential signals, and the number pin is used to supply power or hold. In contrast, the USB interface uses a serial transmission method, and each pin can only transmit one bit of data, so more pins are needed to increase the transfer rate and bandwidth. In addition, the USB protocol also needs to consider issues such as compatibility and device drivers, so its bandwidth and speed are relatively low.
Summary: The high bandwidth of the RJ45 interface is due to the combination of the Ethernet protocol and differential signaling, as well as the ability to support multiple rates and increase the number of signal lines. What do you think about this, welcome to follow my entrepreneur Li Meng and communicate with me!
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