This article helps to understand the difference between Active DAC cable and Passive DAC cable and provides guidance on when to use each type.

Need to understand the difference between Active DAC cable and Passive DAC cable.

The primary type of DAC cable is known as Twinax Cable. It is ideal for ultra short-range connections. DAC supports high-speed connections between servers, switches, and storage devices. DAC cables are lower cost. It is more durable than optical fibers. Also, it is less susceptible to dust and environmental disturbances.

DAC cables can be of two types:

Passive DAC cables—Passive DAC cables transmit signals without the use of electrical components to boost or regenerate the signal. The network equipment's host handles signal amplification and conditioning. Typically, passive DAC cables are limited to a maximum length of seven meters, as their performance diminishes over longer distances.

Active DAC cables — Active DAC cables, in contrast, include an additional driving chip that conditions the signal, enhancing transmission quality over longer distances. These cables share the same setup as passive DAC cables but provide signal boosting through built-in electronics. Active DAC cables can typically extend up to 10 meters or more, offering a longer reach in compare with passive DAC cables. 

You can refer to the Hardware Compatibility Tool to verify the supported distance and cable type for a specific platform: https://apps.juniper.net/hct/category/100001

https://www.juniper.net/documentation/us/en/hardware/800g-optics-cables-guide/optics/topics/concept/800g-cable-length-type.html