Direct Attach Breakout Cable BlueOptics R8M52A-BL 400GBASE-CR8 QSFP-DD to 2×200GBASE-CR4 QSFP56, passive, 2 m, AWG26

Passive Direct Attach Breakout cable BlueOptics R8M52A-BL converts a single 400GBASE-CR8 QSFP-DD interface into two 200GBASE-CR4 QSFP56 connections. The cable uses twin-ax copper with AWG26 conductors and has a 2-meter length, designed for short-reach interconnects inside data centres, server racks and network closets. This passive assembly provides a direct electrical path for 400G-to-2×200G split applications where optical transceivers are not required.

Advantages

The BlueOptics R8M52A-BL offers a simple, low-latency and energy-efficient solution for splitting 400G QSFP-DD ports into two 200G QSFP56 endpoints. Its passive twin-ax construction reduces power consumption compared with active or optical alternatives and eliminates the need for separate transceivers. The 2 m length and AWG26 conductors are suitable for short-distance links commonly found in rack-to-rack or shelf-to-shelf connections.

Suitable for

• Short-reach switch-to-switch connections within the same rack or adjacent racks
• Switch-to-server links that require splitting a 400G port into two 200G ports
• High-density top-of-rack deployments where direct-attach, low-power cabling is preferred

When it may not be suitable

This passive breakout cable is intended for short-reach electrical interconnects; it is not suitable for long-reach connections or where fibre optics are required. It also does not provide media conversion or active signal conditioning, so environments that require extended reach, active equalization, or specific optical transceiver functionality should use appropriate optical modules or active cabling instead.

Key specifications

• Interface: QSFP-DD (400GBASE-CR8) to 2 × QSFP56 (200GBASE-CR4)
• Type: Passive direct attach breakout cable (twin-ax copper)
• Conductor size: AWG26
• Length: 2 metres
• Use case: Short-reach, rack-to-rack or within-rack interconnects
• Power: Passive (no active electronics)

How to use

Install the BlueOptics R8M52A-BL by inserting the QSFP-DD plug into the 400G port on the source device and plugging the two QSFP56 ends into the target devices or breakout ports. Ensure that both ends are fully seated and that devices are powered off or follow hot-plug guidance from the equipment vendor where applicable. Verify link status and configure port speeds and lanes on connected switches or servers as required by your network operating system.

What to consider before purchase

• Confirm that your devices support passive QSFP-DD to QSFP56 breakout functionality and the specific 400G/200G electrical standards
• Ensure the 2 m length and AWG26 twin-ax construction meet your rack layout and signal-budget requirements
• Check vendor compatibility and any port configuration or firmware requirements on switches and servers

Usage recommendations

Use this passive breakout cable for short, stable connections inside racks or between adjacent racks. Avoid tight bends and compressive stress on the cable, maintain recommended bend radius, and route the cable to minimize interference. For longer distances or environments requiring active signal conditioning, select optical modules or active DAC solutions instead.