Comparison of AOC and DAC

AOC is the abbreviation of Active Optical Cables, which is an active optical cable. The active in active light refers to the power supply, that is, when the AOC is working, it needs to use an external power supply to drive the chip to work, exchange optical signals and electrical signals, and transmit signals through optical fibers.

The main types of AOC are SFP+ to SFP+, SFP28 to SFP28, QSFP+ to QSFP+, QSFP+ to 4*SFP+, QSFP28 to QSFP28, QSFP28 to 4*SFP28.

The main advantages of AOC:

1. Lightweight: Since the important part of AOC is the optical cable, it is lighter than DAC.

2. Low degree of electromagnetic interference: AOC transmits optical signals and is not easily affected by electromagnetic interference.

The main disadvantages of AOC:

Slightly higher cost: Compared with DAC, there are more photoelectric conversion modules and lasers, and the cost of AOC is higher than that of DAC.

Difficulty in maintenance: AOC fixes the laser transmitter, laser receiver and fiber optic connector together during the production process, and it is not easy to repair when the laser fails.

DAC is the abbreviation of Direct Attach Cable, which means high-speed cable in Chinese. DAC is both active and passive. In the process of communication, it transmits electrical signals like a twisted pair. Due to the lack of photoelectric conversion equipment, the advantage is particularly obvious in the case of short-distance transmission.

The main types of DAC are SFP+ to SFP+, SFP28 to SFP28, QSFP+ to QSFP+, QSFP+ to 4*SFP+, QSFP28 to QSFP28, QSFP28 to 4*SFP28.

The main advantages of DACs:

1. Low power consumption: Passive DAC does not need a power supply, and the power consumption of active DAC is generally controlled within 500mW in the industry, which can be said to be very prominent for AOC's power consumption of 2W and 3W.

2. Low cost: DAC has no photoelectric conversion unit inside and uses cables for transmission, and the cost is much lower than that of AOC.

The main disadvantages of DACs:

1. Short transmission distance: the cable transmission signal attenuation is too large, and the transmission distance is about six or seven meters.

2. Susceptible to electromagnetic interference: DAC is transmitted by copper cable, which is susceptible to electromagnetic interference.

Transmission distance comparison:

Due to the physical characteristics of the cable itself, in the case of long-distance deployment applications, the transmission speed and signal recognition will be seriously affected by the extended distance. When the transmission wire is changed to optical fiber material, not only the signal quality can be improved, but also the transmission distance will be greatly improved. So in terms of transmission distance, AOC can transmit farther than DAC.

Reliability comparison:

AOC transmits optical signals through optical fibers, and the signal loss is very small during the transmission process, and data can also move at higher speeds and longer distances. DAC transmits electrical signals through copper cables, limited by the physical properties of copper cables, the transmission distance is limited and there are high requirements for anti-electromagnetic interference. AOC is superior to DAC in terms of reliability, and it may have no effect on optical cables in an environment that may have a serious impact on copper cables.

Manufacturing cost versus maintenance cost:

DAC lacks a photoelectric conversion unit that matches AOC. Passive DAC does not consume power during operation, generates less heat than AOC, and requires less cooling than AOC, which can greatly save later operating expenses. Therefore, DAC is better than AOC in manufacturing and post-maintenance.