RJ45 vs CAT6: Key Differences Every Network Installer Must Know
RJ45 is the plastic connector that snaps into an Ethernet port; CAT6 is the twisted-pair cable that carries data inside that port.
Installers often say “I need CAT6 RJ45s” when they mean the cable and the jack. It’s like asking for a “USB-C cable” and then wondering why the port won’t fit—RJ45 is the shape, CAT6 is the stuff inside.
Key Differences
RJ45 is a standardized 8-pin plug or jack; CAT6 is a cable spec rated for 10 Gbps up to 55 m. You can terminate CAT6, CAT5e, or even CAT7 with an RJ45, but you can’t upgrade the plug alone to gain speed.
Which One Should You Choose?
If the job demands 10 Gbps over short runs, pick CAT6 cable terminated with shielded RJ45 jacks. For plain gigabit, CAT5e plus standard RJ45 is cheaper and easier to crimp.
Can I use CAT5e RJ45 on CAT6 cable?
Yes, but performance tops out at 1 Gbps; the plug doesn’t limit speed, the cable spec does.
Does a CAT6 jack look different?
Physically identical to CAT5e RJ45, though shielded versions have metal shells for grounding.
Is CAT6A always better?
Only if you need 10 Gbps past 55 m; otherwise it’s thicker, pricier, and harder to install.