This article provides a systematic introduction to the technical characteristics and interconnection methods of 400G Ethernet DAC cables, offering a reference for 400G network planning and cable selection. 400G Passive Direct Attach Cables (DACs) are key components for building efficient and cost-effective network interconnections. It will guide you. As network speeds escalate to 400G and 800G, proper cabling infrastructure becomes critical for maintaining signal integrity and maximizing performance. DAC copper cables are. As a mature low-power integrated solution recognized by the market, DAC maintains low-latency stability and has also been widely deployed in low-speed networks (such as 10G and 25G). Meanwhile, 400G Ethernet DAC carries higher signal rates over limited copper media, and its underlying technology. QSFP-DD is the most common packaging mode for 400G data centers, and it is a common packaging type for 400G DAC and 400G AOC. It adopts an 8*50GB/S PAM4 electrical modulation format. Ten years ago, passive copper cables solved the.