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Direct Attach Cable (DAC)
Direct Attach Cable (DAC)
Up to 200G, 400G, 800G, 1.6T
400G & 800G DAC Cables | Cost effective QSFP-DD & OSFP
Hot-Pluggable interface
Low latency, low weight, and low power consumption
+3.3V power supply
Suitable for data center and AI server applications
1x: SFP 25G/56G/112G passive and active
Passive maximum 5m for 25G, 3.5m for 56G and 2m for 112G
2x: DSFP 25G/56G/112G per lane passive and active
Passive maximum 5m for 25G, 3.5m for 56G and 2m for 112G
4x: QSFP 10G/25G/56G/112G per lane passive and active
Passive maximum 5m for 25G, 3.5m for 56G and 2m for 112G
8x: QDD 25G/26G/112G per lane passive and active
Passive maximum 5m for 25G, 3m for 56G and 1.5m for 112G
8x: OSFP 25G/26G/112G/200G per lane passive and active
Passive maximum 5m for 25G, 3m for 56G and 1.5m for 112G
Cable Type Selection for GPU Interconnects
Decision Matrix: When to Use Each Cable Type
| Scenario | Cable Type | Reasoning | Example |
| **Within rack, 0-2m** | 400G Passive DAC | Lowest cost, lowest power, sufficient for intra-rack | HGX→ToR switch connection |
| **Within rack, 2-3m** | 400G Passive DAC | Maximum passive distance, still adequate reach | Extended intra-rack runs |
| **Between adjacent racks, 3-7m** | 400G Active DAC (ACC) | Extended reach while maintaining cost advantage | ToR→ToR spine link |
| **Cross-row, 7-30m** | 400G AOC | Optimal balance of distance, power, cost | DataCenter row-to-row |
| **Building-to-building, >30m** | 400G/800G AOC | Only viable option for extreme distances | Multi-facility federation |
When ordering, specify:
[ ] Speed: ie. 400G (PAM4 modulation)
[ ] Form Factor: ie. QSFP-DD (76-pin connector)
[ ] Type: ie. Passive (no active electronics)
[ ] Length: ie. 1m (standard) or 2m (extended)
[ ] Compliance: ie. IEEE 802.3ck, QSFP-DD MSA
[ ] Certifications: ie. RoHS, CE, UL as required
[ ] Quantity: ie. Number of cables needed
[ ] Custom Marking: Pull-tab color (for visual organization), optional EEPROM serial number
Physical Cable Routing Best Practices
Minimize Cable Length
Measure from NIC port to switch port (actual path, not straight-line)
Account for cable tray routing, bend radius constraints
Target lengths: 1m (primary), 1.5m (secondary), 2m (extended)
Order custom lengths if standard options create slack
Organize by Purpose
Separate "uplink" cables (server→switch) from "downlink" cables
Group cables by switch port (all ports A together, all ports B together)
Use cable ties every 0.5 meter along tray
Label both ends of every cable with unique ID
Bend Radius Compliance
Never crimp or kink cables (causes permanent signal degradation)
Use cable guides at 90-degree turns
Avoid running under heavy equipment or server weight
Thermal Management
Never bundle cables under servers (blocks cooling airflow)
Allow 1-2 inches spacing between cable bundles
Route cables above or below server level when possible
Avoid routing near hot equipment (PSU exhaust, etc.)
Connector Protection
Install dust caps on unused connector ports
Keep pull-tab latches accessible (don't trap with cable ties)
Avoid pulling on cable to disconnect—always use latch
Store spare cables with protective caps
Contact Us
Contact Us
SKYCABLE ENTERPRISE CO., LTD.
1F., No. 89, Yongji Rd., Xinyi Dist., Taipei City ,Taiwan
(post code:11070)
TEL:+886-2-27661655
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