Optical Communication Products · Shenzhen, China
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100% Traffic Tested40G QSFP+ Active DAC Cable — FOT Fiber Optic
Click to configure length, jacket and vendor coding — your selection is included in the quote email.

40G QSFP+ Active DAC Cable

SKU: FOT-DAC-40G-A · Category: AOC & DAC Cables

40G QSFP+ active direct attach copper cable, up to 10 m. Factory-terminated, serialized and 100% traffic-tested before shipment.

40GAggregate Bandwidth
≤ 10 mReach
~0.8 WPower / End
Hot-PluggableDesign
Length
3m5m7m10mCustom
Vendor Coding
Generic / MSANVIDIA / MellanoxCiscoAristaJuniperHuaweiHPE
Request a Quote Request Datasheet
Ships worldwide
OEM / ODM welcome
3-year warranty

Product Overview

The 40G QSFP+ Active DAC Cable (FOT-DAC-40G-A) is a factory-terminated active direct attach copper assembly linking one 40G QSFP+ port to a QSFP+ port, delivering full 40G throughput over 30/28 AWG twinax copper at distances of up to 10 m. Active signal conditioning at both ends extends copper reach beyond passive limits while keeping cost well below optics.

Each assembly ships terminated, serialized and 100% traffic-tested: eye-diagram and BER verification on every lane, connector housings inspected, and EEPROM programmed to your requested vendor coding so the cable is recognized natively by your switches and NICs.

OEM branding, custom lengths and mixed-coding ends (different vendor coding on each end) are all supported with short lead times.

Connectivity Diagram

QSFP+40G portQSFP+40G portTwinax copper · up to 10 m

Technical Specifications

Electrical / Optical
Aggregate Data Rate40G (4 × 10G, active equalization)
ConfigurationQSFP+ → QSFP+
Reachup to 10 m
Media30/28 AWG twinax copper
Power Consumption≈0.8 W per end
General
Form Factor AQSFP+
Form Factor BQSFP+
StandardsSFF-8436, QSFP+ MSA
Hot-PluggableYes
Vendor CodingProgrammable — all major platforms
Warranty3 years
Environmental & Mechanical
Operating Temperature0 °C to +70 °C
Storage Temperature−40 °C to +75 °C
Supply Voltage3.3 V
JacketPVC / OFNR
Bend Radius≥ 10× cable Ø (installed)
ComplianceRoHS, REACH, CE

Ordering Information

Part NumberLengthWire GaugeAvailability
FOT-DAC-40G-A-3M3m26 AWG twinaxIn stock
FOT-DAC-40G-A-5M5m26 AWG twinax2–3 weeks
FOT-DAC-40G-A-7M7m26 AWG twinax2–3 weeks
FOT-DAC-40G-A-10M10m26 AWG twinax2–3 weeks
FOT-DAC-40G-A-CUSTOMCustomPer specificationQuoted per order

Need a length that isn't listed? Custom lengths ship in 5–7 days — just note it in your RFQ.

Platform Compatibility

Every cable is EEPROM-programmed at the factory to the vendor coding you specify, so it is recognized natively — no "unsupported transceiver" warnings, no console workarounds. Mixed coding (a different vendor on each end) is available for inter-vendor links.

Generic / MSANVIDIA / MellanoxCiscoAristaJuniperHuaweiHPE

Quality & What's in the Box

100% Traffic Tested

Every lane BER-verified end-to-end on live traffic before packing; eye diagrams sampled per batch.

Serialized & Traceable

Unit serial number links to test record, coding profile and production batch for full traceability.

Test Report Included

Per-order test report available on request; sample reports provided for tender documentation.

Packaging

Individually bagged with pull-tab protector caps, coiled to safe bend radius, export cartons.

Typical Applications

Data Center Fabrics

Spine-leaf and top-of-rack links inside and between adjacent racks.

AI / GPU Clusters

High-radix accelerator fabrics where cost per port and power per bit decide the BOM.

HPC & Storage

InfiniBand-class latency for compute and NVMe-oF storage backends.

Enterprise Core

Cost-effective uplinks between aggregation and core switching layers.

Frequently Asked Questions

When should I choose an active DAC over a passive one?

Choose active when the run exceeds passive copper limits (usually 3–5 m) but you still want copper economics — an active DAC reaches 7–10 m at a fraction of AOC cost. Beyond ~10 m, move to an AOC.

Will it work with my switch brand?

Yes — tell us your platform when ordering and we program the EEPROM with the matching vendor coding (NVIDIA/Mellanox, Cisco, Arista, Juniper, Huawei, HPE or open MSA). Mixed coding on the two ends is available for inter-vendor links.

What are your MOQ and lead time?

Standard configurations ship in 3–7 days with flexible MOQ. Custom OEM/ODM runs are quoted per project — send us your specs for a fast quotation.

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Request a quote for this part

Tell us the platform and the quantity. An engineer checks the part against your switch and software version before quoting — if it will not work, we say so.

Goes to our engineers and the quotation desk together. Replies come from sales@topnetsystem.com, usually within one working day.