RJ45 Crimping Full Guide 🔥 Fix LAN Cable Issues Like a Pro

Start with the Right Tools

You need only a few things: the LAN cable itself (Cat5e or Cat6), RJ45 connectors that match the cable type, a crimping tool, a cable stripper (most crimpers have one built in), a cutter, and a LAN cable tester. Match the connector to the cable — Cat6 cable with Cat5e plugs, or stranded-cable plugs on solid-core cable, gives a weak crimp that fails later. In the video, Anshu works with this basic kit and shows that clean results come from technique, not expensive tools.

Know the T568B Colour Order

Every RJ45 plug has 8 pins, and the wires must sit in one fixed order. The standard used in this guide is T568B. Hold the plug with the pins facing up and the clip facing away from you — pin 1 is on the left. The T568B order from pin 1 to pin 8 is: 1 — White/Orange, 2 — Orange, 3 — White/Green, 4 — Blue, 5 — White/Blue, 6 — Green, 7 — White/Brown, 8 — Brown.

The other standard, T568A, is identical except the orange and green pairs swap places (White/Green first, then Green, then White/Orange and Orange). Both standards work equally well — what matters is using one of them correctly. T568B is the more common choice, and it is the one this video follows.

Strip the Outer Jacket

Slide the stripper over the end of the cable, squeeze gently and rotate once or twice to score the outer jacket, then pull the jacket off — roughly 2.5 to 3 cm (about an inch) is enough to work with. If your cable has a pull string or a plastic cross separator (common in Cat6), trim those back to the jacket edge.

Untwist and Line Up the Wires

Separate the four pairs and untwist each one. Then arrange all eight wires flat, side by side, in the T568B order from Step 2: White/Orange, Orange, White/Green, Blue, White/Blue, Green, White/Brown, Brown. Run your fingers along them a few times to straighten them and press them flat so they stay in order and move as one ribbon.

Trim Even and Insert into the Plug

Hold the eight wires flat in order and cut them straight across in one clean cut, leaving about 12 mm (half an inch) of exposed wire. All eight ends must be exactly level — even one short wire will not reach its contact inside the plug. Now slide the wires into the RJ45 plug, pins up and clip away from you, keeping the order as they go in. Push firmly until every wire end touches the front wall of the plug and the cable jacket itself enters the plug far enough to sit under the crimping bar at the back.

Crimp the Connector Firmly

Place the loaded plug into the 8P slot of the crimping tool and squeeze the handle fully — on a ratchet crimper, squeeze until the ratchet releases. This one action does two things: the gold contacts are pressed down so their teeth bite into each wire, and the plastic bar at the back clamps onto the cable jacket as strain relief. Remove the plug and give the cable a firm tug — it should not move at all. A crimp that slips was not squeezed fully, and that end must be cut off and redone.

Do the Other End the Same Way

Repeat Steps 3 to 6 on the other end of the cable, using the same T568B standard. Same standard on both ends gives a straight-through cable — the normal patch cable used between a PC and a switch, router or wall socket, and the type you will make almost every time.

Test Every Cable You Make

Never trust an untested cable. Plug both ends into a LAN cable tester and switch it on: the lights for pins 1 to 8 should light up in the same sequence on both the main and remote units. A pin that does not light is an open connection, two pins lighting together means a short, and lights in the wrong order mean the wires were arranged incorrectly at one end. The tester tells you exactly which end and which pin is wrong.

And the fix for any failed end is always the same: cut the connector off and crimp a fresh one, following the steps above. A crimped plug is never repaired or reused — this single habit is what separates a reliable homemade cable from the kind that causes the LAN issues this video is about fixing.