Cisco QDD-400G-SR4.2-BD Compatible 400G QSFP-DD SR4.2 Transceiver Module
The QDD-400G-SR4.2-BD compatible module serves equipment requiring a 400G QSFP-DD interface with 850nm,910nm optics and a 70m on OM3 / 150m on OM5 rating. Connection is through MTP/MPO-12 (UPC). Product data, application guidance and factory verification are presented together to support procurement teams match an equipment parts list to a clearly defined optical product.
OEM Part Number: QDD-400G-SR4.2-BDHT Part Number: QDD-SR4.2-400G
Product Highlights
- Compatible alternative to Cisco QDD-400G-SR4.2-BD
- 400G connectivity at 425Gbps
- Optical wavelength: 850nm,910nm
- Specified reach: 70m on OM3 / 150m on OM5
- MTP/MPO-12 (UPC) / MMF interface
- Digital diagnostic monitoring: Supported
- Operating temperature: 0 to 70°C (32 to 158°F)
Specifications
| Cisco Compatible | QDD-400G-SR4.2-BD |
|---|---|
| Manufacturer | HT |
| HT Part Number | QDD-SR4.2-400G |
| Form Factor | QSFP-DD |
| Max. Data Rate | 425Gbps |
| Wavelength | 850nm,910nm |
| Max. Cable Distance | 70m@OM3/150m@OM5 |
| Connector | MTP/MPO-12 (UPC) |
| Media | MMF |
| Transmitter Type | VCSEL 850nm |
| Receiver Type | PIN |
| TX Power | -6.5dBm~4dBm |
| Minimum Receiver Power | -8.5dBm |
| Power Budget | 2dB |
| Receiver Overload | 4dBm |
| Max. Power Consumption | 12W |
| Extinction Ratio | 3dB |
| DDM/DOM | Supported |
| Commercial Temperature Range | 0 to 70°C (32 to 158°F) |
| Modulation (Electrical) | 8x50G-PAM4 |
| Modulation (Optical) | 8x50G-PAM4 |
| DSP | TX and RX |
| Inbuilt FEC | NO |
| Core Size | 50/125µm |
| Packaging Technology | COB |
| Protocols | QSFP-DD MSA, IEEE 802.3-2015 |
Applications and Optical Link Design
Typical deployments include switch-to-switch, switch-to-server and aggregation links inside a data hall or between adjacent equipment rooms. The MTP/MPO-12 (UPC) interface connects to the specified multimode cabling, and the stated reach depends on fiber grade and link loss. Keep this interface on the matching multimode optical standard rather than connecting it directly to a single-mode wavelength or reach variant.
Before deployment, check the host port type, supported data rate and firmware requirements. The 400G interface configuration must match the remote equipment; sharing a QSFP-DD housing alone does not make two transceiver types interoperable.
The multimode channel should use the fiber grade associated with the stated 70m on OM3 / 150m on OM5 reach. Keep the MTP/MPO-12 (UPC) end faces clean and avoid tight bends. Different multimode standards are not interchangeable merely because they share a connector.
Optical Acceptance, Diagnostics and Handling
For this model, the specified transmit-power range is -6.5dBm~4dBm; the stated optical power budget is 2dB. A sound acceptance record includes link state, diagnostic temperature, supply voltage and transmit or receive levels where the host exposes them. Compare the readings with the stated ranges rather than treating any received light as proof of adequate margin. Persistent alarms or borderline values should trigger an end-face and complete-channel inspection. Diagnostic monitoring is listed as Supported. Before every insertion, keep dust caps in place until the patch lead is ready, avoid touching the optical end face and use an appropriate inspection and cleaning procedure. Do not look into an active optical interface.
Procurement and Asset Identification
A useful purchase order identifies the host platform, expected OEM code and optical standard separately. This prevents a module with the same housing but another wavelength, reach or identification profile from being substituted. For mixed deployments, keep one order line per OEM reference and reconcile each received unit with its intended port. For this model, the principal parameters are data rate 425Gbps, wavelength 850nm,910nm, rated reach 70m on OM3 / 150m on OM5.
Cisco Compatibility and Factory Testing
Factory verification starts with the expected QDD-400G-SR4.2-BD identity and finishes with an operating host link. EEPROM data, diagnostic visibility and the stated optical parameters are assessed together. Equipment model, hardware revision and software release can be reviewed before dispatch where platform behavior is uncertain.
Ordering Information
Use QDD-400G-SR4.2-BD as the compatibility cross-reference and QDD-SR4.2-400G as the HT ordering identity. Keep other reaches or wavelength directions on separate order lines. Neutral labels, customer packaging and project-specific compatibility review are available on request.
Quality Assurance and Packaging
Each QDD-400G-SR4.2-BD compatible module is inspected, powered up and functionally checked before protective packing. Dust caps and individual trays shield the interface during transport. Customer references, rack groups and project packing lists can be added for volume orders.
Frequently Asked Questions
Is this an original Cisco transceiver?
No. It is an HT-manufactured compatible alternative for equipment that specifies QDD-400G-SR4.2-BD, not an original Cisco-branded module.
Which fiber and connector are required?
Use MTP/MPO-12 (UPC) with MMF. The specified maximum reach is 70m on OM3 / 150m on OM5, subject to fiber quality and total link loss.
Can it be mixed with another wavelength or reach version?
Only when the two ends share the same optical standard, wavelength plan and supported data rate. Check the exact part numbers and link budget rather than relying only on the module form factor.
Shipping and Lead Time
Standard configurations normally ship within one to three working days, with production lead times confirmed for larger quantities. International courier, air freight and sea freight are available; customer courier accounts and nominated forwarders are accepted.