Quick Summary:
If your Ethernet isn’t fast or stable, don’t blame your router—check your cable. A sloppy CAT6 (RJ45) termination ruins speed, causes dropped signals, and makes meetings glitch. I’ve fixed networks where this tiny step made a huge difference. In this guide, I’ll show you what’s inside a CAT6 cable, how to crimp it right, and how to avoid rookie mistakes that kill performance. Let’s do it the right way—once.
When you strip open a Cat6 cable, you’ll see several parts.
What parts make up a Cat6 cable? The most important are the outer jacket, a rip cord, a spline, and four twisted wire pairs. The jacket protects everything. The rip cord helps remove the jacket. The spline holds pairs apart/ Each pair is twisted tight to fight off noise and signal mix-ups called “crosstalk.”
Why are the wires twisted inside an Ethernet cable? Wires are twisted to cancel out signal noise from nearby cables. This helps your speed stay fast.
That little plastic “X” in the middle? It’s called a spline. The spline keeps the four twisted pairs spaced apart. That makes high speeds more stable.
Now, let’s talk connectors.
What is an RJ45 connector? It’s a small plastic plug with 8 metal pins inside. You need this part to turn raw wire into a working network line. The pins grab each wire and let signals pass through your switch or router port.
Not all Cat6 is the same. There are two types: solid core and stranded.
Solid wire is stiff. It’s great for long wall runs.
Stranded wire bends easy. It’s better for short patch cords.
You may also see jacks instead of plugs. Jacks go into wall plates or patch panels. They look like tiny slots. RJ45 plugs go on cable ends—like the ones you click into your computer. Good Cat6 termination keeps those wires in the right order and untouched too far back.
A tight grip on the cable jacket means more strength, less chance of failure. Get this step wrong, and your internet slows or drops out. Get it right, and your network runs smooth and strong.
A bad Cat6 termination can kill your speed. Right away.
How does a bad termination affect speed?
It lets signal leaks happen. This causes less data to get through fast and clean.
An Ethernet cable works like a train. Each signal is a car on that track. If the track breaks, the train slows or stops. Bad crimps, loose wires, or exposed conductors make the signal bounce or fade out. This gives you dropped calls, games lag, or files that stop mid-copy.
What is crosstalk and how does termination prevent it?
Crosstalk is when one pair of wires leaks its signal into another. It’s like shouting across a quiet room—others hear your talk when they should not.
You stop crosstalk by keeping each twisted pair close, all the way into the RJ45 plug. Don’t untwist past a half inch. That twist blocks the noise. If you mess up the twist, you invite crosstalk.
Does it matter if I use T568A or T568B?
No, both work the same. Just stick with one style through the whole job. Most folks use T568B—it’s more common in networks.
What are signs of a bad crimp?
Slow connections, dropped packets, or even no link at all. If your plug wiggles or the pins look off, cut it off and redo it.
The cable’s outer jacket should tuck just inside the plug. This keeps the small wires safe from pulls and bends. Good cable ends pass the “tug test.” If you lightly pull, nothing should move.
Each pin must pierce the wire’s skin just right. That sharp pin makes the contact. If one pin misses, you lose a whole signal path.
Great terminations are as key as the cable itself. Don’t rush them.
To start, here’s what you need: cable stripper, crimper, flush cutters, and RJ45 plugs.
Step 1: Strip the outer jacket.
Use your cable stripper to remove about 1 to 1.5 inches from the end. Be gentle. You don’t want to nick the wires under the jacket.
Step 2: Prep the wires.
Inside, you’ll see four twisted pairs and a white pull string called a rip cord. Cut the rip cord and any plastic spine. Some Cat6 cables have a spline—it looks like an “X” in the middle. Trim that too.
Next, untwist each pair. Straighten the wires fully.
Step 3: Arrange the wires in T568B order.
What is the color order for T568B?
Answer (high precision): Orange/White, Orange, Green/White, Blue, Blue/White, Green, Brown/White, Brown.
Line the wires left to right in this order. That’s pins 1 to 8.
Step 4: Flatten and align them.
Make sure the wires are flat, not stacked. Pinch them tight. Cut the ends clean so they’re all the same length.
Step 5: Insert the wires into the plug.
Slide them in slow and steady. Check that each wire reaches the front of the plug. The cable jacket needs to go under the clamp in the plug. That gives it a strong hold.
Step 6: Crimp it!
Put the plug into your crimping tool. Squeeze hard until it clicks. That sound means each pin hit the wire right.
Want an easier way? Try a pass-through RJ45 plug. The wires go all the way through the end. You crimp, then trim the extra sticking out. It helps you spot mistakes fast. It’s great for first-timers or fast jobs.
How do I know if my Cat6 termination is good?
Answer: Use an ethernet cable tester and check all lights match their pins (1–1, 2–2, etc.).
When I finish a cable, I always test it with a small LED tester. These tools cost under $20 and work great. I plug in both ends of the cable. Then I switch on the tester. Each light should blink one after the other, in order. If it shows 1-1, 2-2, 3-3, and so on up to 8-8, then the cable is good.
If you see missing lights or numbers out of order, there’s a problem. Here’s what it means:
These errors cause slow speeds or no network at all. If the lights are wrong, I don’t try to fix the plug. I cut off the end and crimp a new one.
Common mistakes cause most of these problems. One is untwisting the wires too far. You should leave the twists close to the plug—within half an inch. Another is not pushing the wires all the way into the connector. If they stop short, they won’t meet the pins.
Look at the plug through the clear plastic. Can you see the copper wires at the end? Did the pins cut into the wire jackets? Is the color order right for T568B? Is the cable jacket inside the plug to stop pulling?
Follow these checks and tests each time. If the tester gives errors, the only fix is to re-terminate. There are no shortcuts that last. Use a good tester like the Klein Tools VDV501-851 for reliable results. Keep your cables working the first time.
Should I use pass-through or standard RJ45 connectors?
Use pass-through plugs if you want easier, quicker, and cleaner ends.
Pass-through RJ45 connectors let you see the wire order before you crimp. This saves time and cuts down on mistakes. Once the wires are in, you trim off the extra bits. You know they reached the end, so your crimp will be solid. I use them for all Cat6 plugs unless I’m short on space.
When should I use a keystone jack instead of an RJ45 plug?
Use a keystone jack on walls or in patch panels—never a plug.
Keystone jacks snap into wall plates and panels. They give a snug and strong hold. You punch the wires down into the jack instead of crimping. This holds the twist longer and gives better speed over long runs. Always use a jack for fixed wiring inside walls.
How can I make my cable ends last longer?
Add a strain relief boot for each plug, and leave a little service loop.
Boots protect the plug where it meets the cable. Without one, that spot bends and fails fast. Pick boots that match your plug style. Slide it on before you crimp.
The service loop is just extra cable coiled in the wall or box. It gives you slack in case you ever need to cut and redo the end.
Keep your cables organized. Use velcro—not zip ties. Zip ties can squeeze your fresh crimp and mess with the signal.
Be sure to always use the same wire order, like T568B. That’s the standard I stick with.
And finally, do a quick tug test after you crimp. If the jacket pulls out, start over. You want that plug tight and strong.
You now know what makes up a Cat6 cable and why each part matters. I showed you how to strip, sort, and crimp using T568B. I warned you what goes wrong with bad crimps and how to test your work. I gave you real tricks for clean, pro-level results that hold up over time. A good Cat6 termination takes care, not luck. Test every line, follow one wiring plan, and make each crimp count.
DCMM LC | Powered by Astrowave © 2025. All Rights Reserved.
