StarTech.com Cisco QSFP-H40G-CU0-5M Compatible 0.5m 40G QSFP+ to QSFP+ Direct Attach Cable Twinax - 40GbE QSFP+ Copper DAC 40 Gbps Low Power Passive Transceiver Module DAC Firepower C9200 C9400

Product Overview

AI-generated summary

For £18.92 ex-VAT for a 0.5m 40G QSFP+ copper DAC, this is the kind of “boring, reliable, get on with it” part that’s usually great value—*if* you’re sure the link is short and you’re using it in the right gear. Passive twinax DACs are low-drama for rack-to-rack connections: they train quickly, draw little power, and generally outperform the hassle of mixing active optics and paying fibre “tax” when you don’t need the reach. On Cisco 40G platforms like the C9200/C9400 family (and similar supported ecosystems), these are often the cost-effective way to spin up lab links, upgrades, and short cabinet patching.

Who should buy: anyone running 40GbE within a top-of-rack / same-rack scenario (roughly half a metre), wanting good performance without active electronics, and okay with the fact it’s a compatibility-driven purchase (i.e., it’ll behave if your switch supports passive 40G DACs and the link is within spec). Who should *avoid* it: if you need longer reach, run in a noisy/high-movement environment (copper DACs are less forgiving than fibre), or you’re deploying into a “no surprises” production network where you’d rather buy the exact OEM part to eliminate compatibility variables. If your cabling is clean and short, this is a sensible buy; if not, spend a bit more—or switch to fibre—because you don’t want to pay troubleshooting time for a cheap cable.