StarTech.com MSA Uncoded Compatible 3m 40G QSFP+ to 4x SFP+ Direct Attach Breakout Cable Twinax - 40GbE QSFP+ to 4x SFP+ Copper DAC 40 Gbps Low Power Passive Transceiver Module DAC

Product Overview

AI-generated summary

For £43.13 ex‑VAT, this is the sort of cheap-and-cheerful DAC breakout cable you buy when you *already* know you’ve got compatible QSFP+ optics/ports on the switch and you just need to get lanes into four SFP+ connections without paying for active optics. In real deployments, it’s best for short, predictable runs (server racks, top-of-rack to patching, same room cabling). It’s passive and low-power, so it tends to be dependable day-to-day and avoids the “mystery behaviour” you sometimes get with sketchier third‑party optics.

That said, it’s not a universal fix. The main reason to be cautious is compatibility: some switches only support specific breakout modes with specific vendor part families, and the “uncoded/MSA compatible” angle helps, but it doesn’t magically guarantee it’ll light up on every platform. If you’re unsure, check your switch’s breakout documentation and whether 40G QSFP+ to 4x10G SFP+ is supported on that exact interface; otherwise you could waste time with link negotiation issues. If you’ve already validated the port support, it’s good value for the money. If you haven’t, spend a little more (or test first) rather than rolling the dice.