Comparison of DAC and AOC Cable

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DAC (Direct Attach Cable) is a low-cost short-distance connection solution that replaces optical modules. Both ends of the high-speed cable have module cable assemblies. The ports cannot be replaced. The module head and the copper cable cannot be separated. In terms of modules, connector modules on high-speed cables do not have expensive optical lasers and other electronic components, resulting in significant cost and power savings in short-distance applications. The common DAC cable types include 10G SFP+ DAC, 40G QSFP+ DAC, 40G QSFP+ breakout DAC,  and 100G QSFP+ DAC.

The high-speed cable DAC is made of silver-plated conductors and foamed insulated core wires, and adopts the method of pair shielding and overall shielding, thus forming a high-speed cable.

The advantages of high-speed cable DAC are as follows:

  1. High performance: suitable for short-distance wiring in data centers, with a wide range of applications and a strong ability to integrate solutions.
  2. Energy saving and environmental protection: The internal material of the high-speed cable is copper core, the natural heat dissipation effect of the copper cable is good, energy-saving and environmental protection.
  3. Low power consumption: High-speed cables have low power consumption. Since the passive cable does not need power, the power consumption is almost zero; the power consumption of the active cable is generally about 440mW.
  4. Low cost: The price of copper cable is much lower than that of optical fiber. Therefore, the use of high-speed cables can greatly reduce the wiring cost of the entire data center.

We know that active optical cables have advantages over high-speed cables in certain aspects, but better results can be achieved by choosing appropriate cables in different scenarios.

The difference between AOC active optical cable and DAC high-speed cable:

  1. Different power consumption, the maximum power consumption of AOC active optical cable is lower than that of DAC high-speed cable.
  2. The transmission distance is different. The transmission distance of AOC active optical cable (OM3) is generally up to 100M, while the transmission distance of DAC high-speed cable is generally about 5-10M.
  3. Different transmission media, AOC active optical cable is made of optical fiber, which belongs to optical fiber communication and is not interfered by electromagnetic waves. The DAC high-speed cable is made of copper wire, which belongs to electrical communication and will be subject to electromagnetic interference.
  4. The transmission signal is different. AOC active optical cable transmits the optical signal, while DAC high-speed cable transmits low-voltage pulse signal.
  5. The price is different. On the one hand, because the price of optical fiber is more expensive than that of copper cable, on the other hand, the modules at both ends of the active optical cable contain optical components, while the DAC high-speed cable does not contain optical components. Therefore, the price of AOC active optical cables is higher than that of copper cables. Much higher than DAC high-speed cables.
  6. The volume and weight are different. Under the same length, the weight of the AOC active optical cable is about one-quarter of the DAC high-speed cable, and the volume is about one-half of the DAC high-speed cable, which is convenient for wiring and transportation.
  7. Different transmission performance, the bit error rate of AOC active optical cable is lower than that of DAC high-speed cable.