D-Link DEM-CB300QXS 40G QSFP+ 3 m Direct Attach Cable
PRODUCT DESCRIPTION
D-Link DEM-CB300QXS 40G Passive QSFP+ Twinaxial Direct Attach Cable, 3 m (DEM-CB300QXS) - 5 Years Local Warranty
40 Gigabit Between Racks
The D-Link DEM-CB300QXS is a 3 m passive twinaxial direct attach copper (DAC) cable with a QSFP+ connector on each end, carrying 40 Gbps Ethernet between two QSFP+ ports. D-Link positions it for the DXS-3600-EM-4QXS 40G module on DXS-3600 switches.
Built to the QSFP+ Standards
30 AWG twinax, 100 Ohm impedance and a 32 mm minimum bend radius, compliant with the SFP MSA, SFF-8436, SFF-8431, EIA 364, EIA-364-1000.01 and UL 94. D-Link rates it for -40 to 85 °C operation.
Need help choosing? Email sales@sourceit.com.sg with your switch model and the ports you want to connect, and we will match the right cable for you.
D-Link DEM-CB300QXS Datasheet — Technical Specifications
General
| Product Name | D-Link DEM-CB300QXS 40G Passive QSFP+ Twinaxial Direct Attach Cable, 3 m |
| Part Number | DEM-CB300QXS |
| Series | 40G Passive QSFP+ Twinaxial Direct Attach Cable Series |
| Local Warranty (Singapore) | 5 years, supplied by SourceIT with a GST invoice |
Cable & Electrical
| Data Rate | 40 Gbps |
| Connector Type | QSFP+ cable assembly (QSFP+ to QSFP+) |
| Cable Length | 3 m |
| Cable Type | Passive twinaxial copper |
| Wire Gauge | 30 AWG |
| Minimum Cable Bend Radius | 32 mm (1.26 in) |
| Cable Characteristic Impedance | 100 Ohms |
| Voltage / Current | 30 V AC / 0.5 A |
| Operating Temperature | -40 to 85 °C (-40 to 185 °F) |
| Certifications | SFP MSA, EIA-364-1000.01, SFF-8436, EIA 364, UL 94, SFF-8431 |
Dimensions and weight are not published by D-Link for this cable.
Compatibility & Software Support
Host Switches
D-Link describes the DEM-CB300QXS as a "3m 40G Direct Attach Copper Cable for DXS-3600-EM-4QXS" and lists it for the DXS-3600 Series (dlink.com product page).
Software
Direct attach cables need no configuration or licence — the host switch detects the cable when it is plugged in.
Package Contents & D-Link Direct Attach Cable Ordering Information
D-Link Direct Attach Cables
| Model | Connectors | Rate | Length |
| DEM-CB100S | SFP+ to SFP+ | 10 Gbps | 1 m |
| DEM-CB300S | SFP+ to SFP+ | 10 Gbps | 3 m |
| DEM-CB700S | SFP+ to SFP+ | 10 Gbps | 7 m |
| DEM-CB100QXS | QSFP+ to QSFP+ | 40 Gbps | 1 m |
| DEM-CB300QXS (this listing) | QSFP+ to QSFP+ | 40 Gbps | 3 m |
| DEM-CB100QXS-4XS | QSFP+ to 4 x SFP+ breakout | 40 Gbps (4 x 10G) | 1 m |
| DEM-CB100Q28 | QSFP28 to QSFP28 | 100 Gbps | 1 m |
| DEM-CB100Q28-4S28 | QSFP28 to 4 x 25G SFP28 breakout | 100 Gbps (4 x 25G) | Not stated in datasheet |
| DEM-CB50CXP | CXP to CXP (stacking) | 120 Gbps (12 x 10G) | 0.5 m |
Package contents are not listed in D-Link's datasheet — ask us if you need confirmation of what is in the box.
Datasheet & Downloads
| D-Link datasheet | DEM-CBx00QXS Series A1 Datasheet, updated Feb 2013 (PDF) |
| D-Link datasheet | 40G Passive QSFP+ Direct Attach Cable Series A1 Datasheet v1.00 WW (PDF) |
| D-Link product page | DEM-CB300QXS on dlink.com |
Need a PDF sent directly? Email sales@sourceit.com.sg quoting DEM-CB300QXS.
Frequently Asked Questions — D-Link DEM-CB300QXS
Is this a QSFP+ to SFP+ cable?
No. The D-Link datasheet describes it as a 3 m 40G passive QSFP+ twinaxial cable with QSFP+ on both ends. For a QSFP+ to 4 x SFP+ breakout, see the DEM-CB100QXS-4XS.
Which switches is it for?
The DXS-3600 Series with the DXS-3600-EM-4QXS module, per D-Link.
Is this model still current?
D-Link's global site (dlink.com/en) shows the DEM-CB300QXS as Live with support to 2 May 2027, while D-Link UK lists it End of Sale (phased out 5 Feb 2022, support to 5 Feb 2027). Please email us to confirm availability before ordering.
What warranty do I get?
5 years local warranty in Singapore, supplied by SourceIT with a GST invoice.
