CX4 FAQs

1. Is there a difference between InfiniBand™ and 10 GbE-CX4 cable assemblies? Aren’t they the same?
2. What is the maximum length Gore assembly that I can use in a 10 GbE–CX4 system?
3. I need an assembly that is very flexible for routing purposes. Can I still go to long lengths?
4. I need an interconnect with standard CX4 connectors, but my signaling application is nothing like the CX4 specification. Will these assemblies work?

1. Is there a difference between InfiniBand™ and 10 GbE-CX4 cable assemblies? Aren’t they the same?

Although the assemblies for InfiniBand™ and CX4 appear to be identical at first glance, they are certainly different. True, the connectors and basic cable design for the two standards are the same, but the IB and CX4 specifications are fundamentally different. The primary difference is that the IB specification allows for passive equalization in the cable assembly, where the CX4 specification does not. In terms of Gore assemblies, this means that Eye-Opener +™ conductor is used in our InfiniBand™ assemblies, and standard copper conductor is used in our CX4 cable assemblies. There are other design subtleties in Gore’s IB and CX4 cable assemblies to ensure compliance with the separate specifications. In order to make our IB and CX4 products visually distinct, Gore InfiniBand™ cables will have the standard black cable jacket, while the CX4 cable assemblies will have a sky-blue cable jacket.

2. What is the maximum length Gore assembly that I can use in a 10 GbE–CX4 system?

The answer depends on a number of factors. The principle consideration is the type of signal driver and receiver used. If the driver is in strict compliance with the IEEE specification (i.e. supports the appropriate launch voltage, de-emphasis levels, etc. . ), then the supposed maximum length indicated in the IEEE specification is 15 meters. However, Gore 24 AWG 10GbE-CX4 assemblies can meet the IEEE insertion loss specification to a length of 20 meters! Little is said about the receiver used in CX4 systems, other than the fact that 15-meter cable lengths should be supported. Non-standard or proprietary systems that use more exotic drivers and receivers can drive cable lengths exceeding 20 meters. Contact Gore to determine the maximum length that can be supported in your application.

3. I need an assembly that is very flexible for routing purposes. Can I still go to long lengths?

In order to get a more flexible cable, the cable OD must be reduced which means using smaller conductors. Smaller conductors have larger resistive losses, which reduce the effective maximum length of the assembly. For a specific application, the best place to start is to determine the minimum bend radius that the cable will need to support and the maximum assembly length required. With this information, contact Gore to discuss an interconnect design strategy for your application.

4. I need an interconnect with standard CX4 connectors, but my signaling application is nothing like the CX4 specification. Will these assemblies work?

In many cases, Gore's CX4 assemblies will function properly in applications using different signal specifications. Contact Gore and ask to speak with an applications engineer on the CX4 team. He or she will review your application requirements and help you to develop the optimal solution.