StarTech.com Cisco QSFP-4SFP10G-CU5M Compatible 5m 40G QSFP+ to 4x SFP+ Direct Attach Breakout Cable Twinax - 40GbE QSFP+ Copper DAC - Low Power Passive Transceiver Module DAC - Cisco Firepower, C9300, C3850

Product Overview

AI-generated summary

If you’ve got QSFP+ 40GbE ports on a Cisco switch and you need four 10GbE links without touching optics, this is the kind of cheap-and-practical DAC breakout cable that actually earns its keep. For £53.44 ex-VAT for a 5m, it’s very good value *when it works in your exact port/module ecosystem*. It’s passive and low power, so there’s less to go wrong than with active copper—just plug it in and move on with your day, assuming your switch is happy with third-party copper.

That said, I’d only buy this if you’ve already confirmed compatibility with your specific Cisco model/IOS and port type (e.g., certain platforms are picky about breakout DACs and supported part-number behavior). Also, 5m is fine for typical rack-to-rack or within-cabinet runs, but if your cable path is tight and you’re pushing the length, don’t assume it’ll behave—copper DACs can be less forgiving than optics in marginal installs. If you need maximum “it will definitely link up first time” confidence, OEM optics or a Cisco-approved solution can cost more but save hours of troubleshooting; this is best for straightforward lab/datacentre patching where you can validate quickly.