Direct Attach Cable (DAC) is used in data centers. It provides low latency, low power consumption, low cost, and high-density alternative cabling solution for high-speed 10G-400G interconnect to fiber optic transceivers.

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Direct Attach Cable (DAC) is used in data centers. It provides low latency, low power consumption, low
cost, and high-density alternative cabling solution for high-speed 10G-400G interconnect to fiber optic
transceivers. This article will introduce DAC cable and its types and applications.
What is a Direct Attach Cable?
A direct attach cable (DAC), also called direct copper cable or high-speed cable is a type of
factory-terminated Twinax cable that connects directly into transceivers and can be brought in
several lengths for short distances of up to 15 meters. DAC cable consists of fixed lengths of
shielded copper coaxial or fiber optic cable with fixed pluggable transceivers on either end with
varying gauges from 24 to 30AWG. DAC cable can achieve interconnection up to 15m via twin
axial copper cable, and reach 100m over active optical cable at 10Gbps, 40Gbps, or beyond.

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Direct Attach Cable Types
There are different types of DAC cables: direct, breakout, passive and active. Direct DAC cable
provides a direct connection from one port to another. Breakout DAC cable enables one port to be
connected to 4 ports. Passive DAC cable has no electrical components built into the cable
assembly. Hence, it has a minimal power consumption of no more than 0.15w and generally for
short reach up to 7m. Active DAC cable has electrical components in the connectors that can
boost signal levels, allowing reaching greater distances (5m or more) via copper media and
ensuring better transmission quality.

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Features and Benefits
DAC cable provides high reliability, high speed, high density, low cost, low power consumption,
low latency, excellent attenuation performance, anti-interference in high-frequency broadband
transmission, energy saving and environmental protection, strong interchangeability, and ease of
installation.
Application
DAC cable is used in high-speed interconnect applications such as data centers, local area
networks (LAN), high-performance computing (HPC), storage area networks (SAN), serial
advanced technology attachment (SATA) storage devices, routers, switches, servers for
10G/40G/100G Ethernet, and InfiniBand. Generally speaking, DAC cable provides a cost-effective
solution for the following applications:
 Top of rack(ToR) / Adjacent rack – Passive and active DAC cable is suitable for shorter ToR or
adjacent racks with cost-effective budgets.

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 Middle of Row – As long as the distance is no more than 15m, the active DAC cable may be
the best solution in this application.
 End of Row – DAC cables are ideal for the end of row architectures as long as the distance is
within the 15 meters limit.
Conclusion
DAC cable is a high-speed and low-cost short-distance connectivity solution to replace optical
transceiver modules. It is designed to meet the growing need for higher bandwidth in data
centers, storage area networks, and HPC applications by connecting switches to routers or servers.
Sun Telecom specializes in providing one-stop total fiber optic solutions for all fiber optic
application industries worldwide. Contact us if any needs.