Uniqcli

DAC cables

Direct attach twinax assemblies with the transceivers moulded on — filter by length, or search inside the page by platform, brand or part number.

Showing 24 of 4,465 DAC cables

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Specifications are read from the manufacturer product title as supplied to us; where a value is not stated it is left blank rather than estimated. Every line is screened for TAA country-of-origin and NDAA §889 status before checkout.

About DAC cables

A DAC is a fixed-length twinax copper assembly with the transceivers permanently attached at both ends. That construction is the whole point: inside a rack, where a top-of-rack switch is a metre or two from the servers it feeds, a DAC replaces two optics and a fibre jumper with one part that costs a fraction as much, draws almost no power and adds essentially no latency. At scale — a row of racks, four uplinks each — the saving in both money and watts is the reason DACs are the default for intra-rack 10, 25, 40 and 100 Gb links rather than an economy option. They come in passive and active forms, in SFP+, SFP28, QSFP+ and QSFP28 housings, and as breakout assemblies that fan one high-speed port into four slower ones.

Two constraints decide whether a DAC will work for you. The first is reach, and it is short: passive twinax is generally good for about 3 metres at 25 Gb per lane and up to 5 metres — occasionally 7 — at 10 Gb, while active DACs add signal conditioning and stretch to roughly 10 metres. Beyond that the cable stops being the cheap option and an active optical assembly or a pair of optics with a fibre jumper takes over. The second is compatibility: a DAC's attached transceivers are coded for a switch platform, third-party assemblies state in their title which platform they are built for, and some switches need to be told to accept a transceiver they did not sell you. Confirm the platform at both ends before ordering. Lengths on this page are shown in feet, converted from the metre lengths these assemblies are almost always printed in — a 3 m cable appears as 9.8 ft — and every specification on a card is read from the manufacturer's own title.

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FAQ

DAC cables questions

DAC, AOC or optics and fibre?
DAC inside the rack or to the rack next door: cheapest, lowest power, no optics to buy. AOC — an active optical assembly, which is a separate page here — when you need tens of metres with a thin, light cable that ignores electrical noise. Optics plus a fibre jumper when the run is long, when you want to reuse structured cabling, or when the two ends need different optics. Cost per link rises in roughly that order.
How long can a DAC be?
Shorter than most people expect. Passive twinax is typically specified to about 3 metres at 25 Gb per lane and up to 5 metres, sometimes 7, at 10 Gb; active DACs include signal conditioning and reach roughly 10 metres. Those are the practical limits — a passive cable run past its specification does not degrade gracefully, it fails to link or produces errors. Past about 10 metres, switch to AOC or optics.
Will a DAC work in my switch?
It depends on the coding of the attached transceivers. Assemblies are programmed for a specific switch platform, and a third-party cable states in its title which platform it is built to work with — so the part you need depends on the equipment at both ends, which may not be the same vendor. Some switches also require unsupported-transceiver acceptance to be enabled. Tell us the switch models with your quote request and we confirm the coding against the exact part numbers.
Some of these say TAA compliant. Does that cover my requirement?
That wording is the manufacturer's own statement about its own product, and it is not something we restate on your behalf. Country of origin varies by part number and by production run, so every line is screened for TAA country-of-origin and NDAA §889 status before checkout — state the requirement with your quote request and we confirm it against the exact SKUs you are ordering.

Cabling a top-of-rack build?

Send the switch and NIC models, the link speeds and the lengths you need. We confirm the coding at both ends, check stock across the quantity and return a complete quote — including the breakout assemblies if you need them.

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DAC Cables — Direct Attach Twinax — Uniqcli