The Dell FC6KV is a 3-metre 40GBASE-CR4 passive direct attach twinax cable with a fixed QSFP+ connector at each end, carrying 40 Gbps across four 10 Gbps lanes. It is Dell's DAC-QSFP-40G-3M and it is the most-used length in the 40G copper family.
Where it belongs
Three metres covers the common cases: switch to server within a rack, or a pair of switches at opposite ends of the same cabinet. It is long enough to route properly through vertical cable management rather than stretching across the front of equipment, and short enough to stay flexible.
Because the assembly is passive, there are no transceiver electronics at either end. No power draw, no optical budget to calculate, nothing to fail. For links inside one rack this is both the cheapest and the most reliable way to land 40 Gbps.
Where it stops being the right answer
Copper at 40G runs out at around 5 m. Past that you move to active optical cable or to QSFP+ optics over fibre. The other reason to skip a DAC is breakout - if you intend to split one QSFP+ port into four 10GbE SFP+ connections you need the QSFP+-to-4xSFP+ breakout cable, not a point-to-point assembly like this one.
Which switches take it
Any Dell switch with QSFP+ ports: S4048-ON, S4048T-ON, S4148F-ON, S4148T-ON, S4248FB-ON, S6000-ON, S6010-ON, N4064 and N4064F.
Condition
Refurbished, tested and covered with warranty.
Related models
Specifications
| Dell model designation | DAC-QSFP-40G-3M |
|---|---|
| Standard | 40GBASE-CR4 (QSFP+ direct attach copper) |
| Cable length | 3 m (10 ft) |
| Connector | QSFP+ to QSFP+ |
| Transmission medium | Passive copper twinax |
| Data rate | 40 Gbps aggregate over 4 x 10 Gbps lanes |
| Power dissipation | None - passive assembly |
| Shipping weight | NetSuite carries 0 lbs on this item - see verification notes |
