Arista H-D400-4Q100-5M-Arista | 400G QSFP-DD to 4x 100G QSFP28 Active Copper Cable, 5m

Q: What is the difference between active and passive copper cables?
A: Active copper cables like the H-D400-4Q100-5M contain integrated signal processing electronics to extend reach and improve signal integrity. This allows for longer cable lengths (up to 5m) compared to passive DACs which are typically limited to 3m or less.

Q: Can this cable connect Arista switches to other vendors' equipment?
A: Yes, while branded for Arista, this cable follows industry-standard QSFP-DD and QSFP28 MSA specifications. It will work with any compliant 400G QSFP-DD and 100G QSFP28 ports from major networking vendors, provided proper coding is in place.

Q: What is the gearbox function in this cable?
A: The integrated gearbox converts the 8x 50Gbps PAM-4 electrical lanes from the 400G QSFP-DD port into 16x 25Gbps NRZ lanes distributed across four 100G QSFP28 connectors (4 lanes per connector). This enables seamless connectivity between different signaling technologies.

Q: Is this cable suitable for long-distance connections?
A: This 5-meter active copper cable is designed for short-reach data centre connections within racks or between adjacent racks. For longer distances, consider active optical cables (AOCs) or fibre optic transceivers.

Q: Does this cable require special configuration on the switch?
A: The cable is hot-pluggable and typically auto-negotiates. However, you may need to configure the 400G port for 4x100G breakout mode in your switch operating system. Consult your switch documentation for specific breakout configuration commands.