![Icon [all products]](https://www.thunder-link.com/tl-content/uploads/2022/05/Icon-all-products-1.svg "Icon [all products]"){kind=icon}
All productsIn nowadays data-driven environment, high-speed data transmission is critical for the efficient operation of data centers and cloud computing. Two of the most commonly used solutions for high-speed connectivity are Active Optical Cables (AOC) and Direct Attach Copper Cables (DAC). T
While both serve the purpose of transmitting data at high speeds, they differ significantly in terms of technology, performance, and application. This article explores the key differences between AOC and DAC, helping you choose based on your specific needs.
Technology and Construction
AOC utilizes optical fibers to transmit data as light signals. It incorporates optical transceivers at both ends to convert electrical signals into optical signals and vice versa. This technology allows AOC to achieve high bandwidth and long-distance transmission with minimal signal loss.
DAC relies on copper cables to transmit electrical signals directly. It is essentially a copper cable with connectors on both ends, designed for short-distance, high-speed data transmission. DAC cables come in two variants: passive DAC, which has no active components, and active DAC, which includes signal amplification to extend the transmission distance.
Key Differences
| Feature | AOC (Active Optical Cable) | DAC (Direct Attach Copper) |
| Transmission Medium | Optical fiber (light signals) | Copper cable (electrical signals) |
| Transmission Distance | Long-distance (up to 100 meters or more) | Short-distance (Passive DAC: ≤7m; Active DAC: ≤15m) |
| EMI Resistance | Immune to electromagnetic interference (EMI) | Susceptible to electromagnetic interference (EMI) |
| Cable Weight | Lighter and more flexible | Heavier and less flexible |
| Power Consumption | Higher (requires optical-electrical conversion) | Lower (especially passive DAC, minimal power consumption) |
| Cost | Higher (due to fiber and transceivers) | Lower (copper cables are cheaper) |
| Latency | Slightly higher (due to signal conversion) | Lower (direct electrical signal transmission) |
| Use Cases | Long-distance, high-density, high-EMI environments | Short-distance, cost-sensitive, low-EMI environments |
| Typical Applications | Cross-rack, cross-room, or cross-floor connections | Within-rack or adjacent-rack connections |
| Compatibility | Compatible with standard interfaces (e.g., SFP+, QSFP+) | Compatible with standard interfaces (e.g., SFP+, QSFP+) |
| Signal Attenuation | Low signal attenuation, suitable for long distances | Higher signal attenuation, suitable for short distances |
| Cable Management | Easier to manage (lightweight and flexible) | More challenging (heavier and stiffer) |
Applications
AOC: Supports long-distance transmission and strong anti-interference, which is normally deployed in different racks, rooms or floors between switch and switch, router and router, or switch and router.
DAC: Specialized in short-distance transmission, so popular used within the same rack, such as servers to switches in a data center.
Test case on Huawei switch
QSFP-100G-AOC-10M
100GE0/0/1 transceiver information: ------------------------------------------------------------- Common information: Transceiver Type :100GBASE_Active_Optical_Cable_QSFP28 Connector Type :No separable connector Wavelength(nm) :850 Transfer Distance(m) :10(Optical Cable) Digital Diagnostic Monitoring :NO Vendor Name :Hisense Vendor Part Number :DQF8503-4C10 Ordering Name : ------------------------------------------------------------- Manufacture information: Manu. Serial Number :S51D8EA003F Vendor Name :Hisense ------------------------------------------------------------- Diagnostic information: Transceiver does not support diagnostic information.
QSFP-100G-CU2M
100GE0/0/6 transceiver information: ------------------------------------------------------------- Common information: Transceiver Type: 100GBASE_CR4_QSFP28 Connector Type: No separable connector Transfer Distance(m) :2(copper) Digital Diagnostic Monitoring: .NO vendor Name:LUXSHARE-ICT vendor Part Number:L99QF029-SD-R ------------------------------------------------------------- Manufacture information: Manu.serial Number:Z00A2R2033002210 vendor Name:LUXSHARE-ICT ------------------------------------------------------------- Diagnostic information: Transceiver does not support diagnostic information.
Whether you’re evaluating AOC or DAC cable for your data center, or sourcing peripheral switches or routers, or simply need expert advice on high-speed connectivity solutions—we’re here to help!
