DAC and AOC Cables

Direct attach cables and active optical cables are the two ways to connect equipment at short range without a separate transceiver at each end, and the choice between them comes down to distance and medium. A direct attach cable, usually called a DAC, is a copper cable with a transceiver-like connector at each end: simple, inexpensive, and limited to short runs, typically within a rack or between adjacent racks. An active optical cable, usually called an AOC, replaces the copper with fiber and active electronics in the connectors: longer reach than a DAC, lighter and thinner, and more expensive. This page covers both at category level, because the catalogue lists DAC and AOC cabling as a category name without a published product page behind it.

The speed options in this guide are 25G and 100G DAC cables and QSFP28 DAC options, which are the frozen search terms that map to this page. A 25G DAC suits a single 25G link within a rack, such as a server to a top-of-rack switch. A 100G DAC suits a 100G link within a rack or between adjacent racks, and a QSFP28 DAC is the 100G form of that cable. In each case the cable is a fixed assembly: the connectors are part of the cable, the length is fixed at manufacture, and the buyer chooses the length when ordering rather than cutting cable on site.

The practical questions for a DAC or AOC purchase are short. What speed must the link run at, and in which form factor. How long is the run, measured along the actual cable route rather than the straight-line distance between racks. Whether the run stays inside one rack, crosses to an adjacent rack, or goes further, because that decides DAC against AOC. And whether the equipment at each end accepts the connector type the cable carries, because a DAC or AOC cannot be re-terminated in the field. A buyer who states those four answers during the inquiry will get a specific answer.

This page is deliberately a category page, not a product page. No cable model, length option, loss figure or connector specification is stated here, because none has been published for a DAC or AOC product. The category name is stated because it appears in the catalogue navigation, and the speed options are stated because they are the search terms that map to this page. A buyer who needs a specific cable should state the requirement — speed, form factor, length and equipment at each end — during the inquiry.

Before ordering, confirm quantity, price and delivery time during the inquiry. Certificates are available upon request.