Will a Cat6 ethernet cable work on a router/NIC that only supports cat5 speeds?

I know that it won't give me cat6 speeds but will it even work in the first place?

2 Answers 2


Yep, Category 6 cable, commonly referred to as Cat 6, is a standardized cable for Gigabit Ethernet and other network physical layers that is backward compatible with the Category 5/5e and Category 3 cable standards. More


To expand on t3mp's answer, the standard defines loss characteristics that the cabling need to meet and not the design of the cable itself.

The cabling isn't actually Cat 6 or Cat 5/5e until it's installed and tested. Until then, it's all just unshielded twisted pair (UTP) with TIA/EIA-568 modular connectors. If the cabling is certified to meet Cat 6, it also meets Cat 5/5e.

  • "The cabling isn't actually Cat 6 or Cat 5/5e until it's installed and tested." -> This isn't true. The gauge of the twisted pairs in Cat6 is noticeably thicker than that of Cat5 or earlier. So while yes, the "category" rating has more to do with the specs of the cabling, there is a physical difference between them. Jan 15, 2015 at 16:23
  • Thicker gauge cabling isn't Cat 6 if it's run across the ballast of a flourescent light. I'd say it's more accurate to say there are differences in the cable capable of meeting Cat 6 standards. Jan 15, 2015 at 16:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.