What Sets AOC, DAC, and ACC Apart for 800G Interconnects in Modern Data Centers?

If you’re rolling out 800G leaf-spine network fabrics or upgrading your data center interconnect infrastructure, choosing the right copper/fiber interconnect is one of the most impactful decisions for cost, power, and performance. Let’s break down the key differences and ideal use cases for DAC, ACC, and AOC aligned with today’s 800G deployment needs.

1. Direct Attach Copper (DAC): Passive Copper for Shortest-Reach 800G Connections

Direct Attach Cables are fully passive copper assemblies—no integrated signal amplification or active electronics built into the connectors. That makes them the lowest-cost, lowest-power option for ultra-short-reach rack-level interconnections.

• Typical reach: 0.5m to 3m for 800G applications (as shown in the diagram, this covers 800G-to-800G, 800G-to-2x400G, and 800G-to-4x200G breakouts)
• Key pros: No external power required, zero latency added, lowest Bill of Materials (BOM) cost, compact form factor
• Ideal data center use cases: Top-of-Rack (ToR) switch to server connections within the same rack, or intra-rack cross-connections where you don’t need extra length. Passive DAC is perfect for low-power 800G server deployments where every watt of switching power matters.

2. Active Copper Cables (ACC): Active Signal Conditioning for Extended Copper Reach

Unlike passive DAC, ACC integrates small active signal boosting electronics directly into the connector heads to compensate for copper signal loss at higher speeds and longer lengths.

• Typical reach: 1m to 5m for 800G (extended past the maximum range of passive 800G DAC)
• Key pros: Lower cost and lower power consumption than AOC for reaches 2-5m, simpler deployment than fiber, retains the smaller form factor of copper vs. fiber transceivers
• Ideal data center use cases: Same-rack or adjacent-rack interconnections that exceed passive DAC’s maximum length. If you need a 4m 800G breakout connection from a 800G leaf switch to multiple end devices, ACC delivers better signal integrity than passive DAC without the cost of fiber.

3. Active Optical Cables (AOC): Fiber-Based Interconnects for Medium-to-Long Reach

AOC replaces copper with multimode or single-mode optical fiber, with integrated transceivers built directly into the cable assembly (no discrete optical transceivers required).

• Typical reach: 3m up to 100m for multimode AOC, 1m up to 2000km+ for single-mode AOC transceivers (as outlined in the diagram)
• Key pros: Immunity to electromagnetic interference (EMI), much lighter weight than copper for long runs, supports far longer reaches than any copper cable, lower signal loss at 800G speeds
• Ideal data center use cases: Inter-rack connections between leaf and spine switches in different rows, campus data center interconnects (DCI), any 800G link that exceeds 5m. Multimode AOC is the go-to for 10-100m spine-leaf connections, while single-mode AOC is used for longer cross-campus or metro DCI links. AOC is also available in breakout configurations (800G-to-2x400G / 800G-to-4x200G) to match your network splitting needs.

Quick Decision Guide for 800G Data Center Interconnect

When architecting your 800G infrastructure, matching the interconnect type to your reach requirement eliminates unnecessary cost and power waste while guaranteeing reliable performance. All three form factors are available in straight 800G and breakout configurations to fit modern modular switch designs.