QNAP Qsfp Dac Cable - CAB-NIC40G30M-QSFP

QNAP CAB-NIC40G30M-QSFP QSFP DAC Direct Attach Cable 40GbE 3M

Overview

The CAB-NIC40G30M-QSFP is a 40GbE QSFP direct attach copper (DAC) cable in a 3.0-meter length, designed to connect QNAP 40GbE NICs to compatible switches or NAS-to-NAS back-end links without the latency or cost overhead of optical transceivers. DAC cables carry full 40GbE bandwidth over a passive copper assembly — no SFP optics, no media converters, no additional power draw. For short rack-to-rack or top-of-rack switch runs where 3 meters is sufficient, this is the lowest-complexity path to a full-bandwidth 40GbE link.

Compatibility

Designed for QNAP NAS and expansion systems equipped with 40GbE NIC interfaces, including QNAP NAS models fitted with QSFP-port network adapters. The QSFP connector format is industry-standard, making this cable cross-compatible with 40GbE QSFP ports on third-party switches and servers — though QNAP validates it specifically against their own 40GbE NIC-equipped NAS platforms. Confirm your switch or peer device accepts passive DAC cables at 40GbE QSFP before ordering; some managed switches require active DAC or optical modules for specific port configurations. For longer runs beyond 3 meters, a fiber-optic transceiver pair is the appropriate alternative — passive copper DAC is generally limited to 7 meters maximum under 40GBASE-CR4.

Installation Notes

DAC cables are passive assemblies — plug and connect, no driver or firmware required. The QSFP locking bail must be fully seated and latched on both ends before powering the link; a half-seated QSFP is a common cause of no-link or intermittent errors at 40GbE. Route with a bend radius no tighter than the cable's rated minimum to avoid signal degradation — standard copper DAC spec is typically 30mm minimum bend radius. No tools required for installation.