1. What is a DAC?
Direct Attach Cable, or DAC for short, is generally translated as a direct connection cable or a direct connection copper cable. It is a cable assembly with fixed connectors at both ends, and is usually purchased at a fixed length. DAC is divided into two types: passive DAC (Passive Copper Cable) and active DAC (Active Copper Cable). The DAC transmits all electrical signals, and does not involve the conversion of electricity to light or light to electricity.
2.Passive DACs use shielded high-speed differential copper cables. There are no chips on the circuit boards at both ends, and no signal processing is done during the entire signal transmission process. Passive DAC is the preferred solution for short-distance applications. It is widely used in data transmission between the same cabinet or adjacent cabinets in the data center. Its biggest features are low cost, ultra-low power consumption (less than 0.1 watts) and high reliability.
3.The active DAC is similar to the passive DAC. It also uses shielded high-speed differential copper cables, but it has high-speed electrical signal compensation chips such as pre-emphasis and equalization to compensate for the attenuation of the electrical signal during transmission. Such as the data transmission distance between devices (refer to Figure 2). Compared with passive DAC, its biggest feature is that the cable used is thinner and the transmission distance is longer.
