RJ45 Crimping Complete Guide Tools Pinout Technique and Testing
A bad crimp is behind most dead LAN points, 100 Mbps links on gigabit networks and cameras that drop offline. This guide covers the full job - tools, the exact T568B wire order, clean technique and proper testing.
Technical AnshuCat5e and Cat6T568B Pinout
Watch the full RJ45 crimping guide on video - every step shown live, from stripping the cable to the final tester check
Making your own LAN cable is a core networking skill, and it is not hard - but small mistakes hide well. A plug can look perfect and still drop one wire. Follow the steps in order: right tools, clean strip, exact order, full seating, firm crimp, and a real test. The full process is shown live in the video above.
T568B Pinout - Pins 1 to 8, Plug Contacts Facing You
Pin 1White-Orange
Pin 2Orange
Pin 3White-Green
Pin 4Blue
Pin 5White-Blue
Pin 6Green
Pin 7White-Brown
Pin 8Brown
The T568B order used through this guide. Both ends of a normal LAN cable use this same order - that is a straight-through cable.
1
Tools You Need Before You Start
RJ45 plugs matched to your cable - Cat5e plugs for Cat5e cable, Cat6 plugs for Cat6 cable. The wire holes are sized differently
Crimping tool - a ratcheting crimper gives a full, even crimp. If you use pass-through plugs, the tool must be a pass-through type that trims the wires flush
Cable stripper - the small round stripper that scores only the jacket. A knife works in an emergency but nicks conductors
Flush cutter or scissors - to trim the eight wires square and equal
Cable tester with a remote unit - the two-piece tester that lights wires 1 to 8 in sequence at both ends
Strain relief boots - slide one onto the cable before you crimp. It cannot be added afterwards
2
Strip the Jacket Without Nicking the Wires
Slide the boot onto the cable first, narrow end facing the end you are about to crimp
Strip about 3 to 4 cm of outer jacket with the stripper - one or two gentle turns, then pull the jacket off
Cut away the ripcord and any plastic wrapping. On Cat6 cable, snip out the cross-shaped plastic separator at the jacket line
Inspect the eight conductors under good light. A nick in the copper is a future break - if you see one, cut the end off and strip again
3
Arrange the Wires in T568B Order
Untwist each pair only as much as needed and lay the wires flat in this order: white-orange, orange, white-green, blue, white-blue, green, white-brown, brown
Keep the untwisted length short - about 13 mm (half an inch) or less. Long untwisted sections hurt performance at gigabit speed
Comb the wires flat between your fingers, check the order twice, then trim the ends square so all eight are exactly equal, about 12 to 14 mm exposed
The blue pair sits in the middle (pins 4 and 5) and the green pair is split around it (pins 3 and 6). That split is normal and correct
4
Insert and Crimp - the Step That Decides Everything
Push the wires into the plug until every conductor touches the front wall of the plug. Look through the clear plastic and confirm all eight tips are fully forward
Check that the cable jacket also enters the plug by about 6 mm, so the plug's crimp bar will bite the jacket, not just the thin wires
Confirm the colour order one last time through the plug body - this is the last free check. After crimping there is no undo
Insert the plug into the 8P die of the crimper and squeeze fully. A ratcheting tool releases only after a complete crimp - let it finish
Give the cable a firm tug. A correct crimp does not move at all
5
Test Every Cable You Make
Connect the tester main unit to one end and the remote unit to the other
Watch both ends: lights 1 to 8 must blink in the same order on both units, with no light missing, doubled or out of sequence
A missing light means an open wire - usually a conductor that did not reach the front of the plug. Cut the plug off and redo that end
Then plug the cable into a real switch and PC and confirm the link speed shows 1.0 Gbps, not 100 Mbps
Honest note: a basic cable tester proves the wires are connected in the right order. It does not certify that a cable will carry gigabit cleanly over a long run - split pairs and damaged cable can pass a simple tester and still fail in real use. The final proof is always a live link test at full speed.
Watch the Full RJ45 Crimping Video
See the crimping technique live on camera - wire order, seating depth and tester reading, exactly as done in this guide.
Which pinout should a beginner use, T568A or T568B?
Use T568B at both ends. It is the most common standard in offices and homes, so your cable will match existing wiring. Either standard works electrically - mixing them on the two ends of one cable is what creates a crossover cable.
How much wire should be exposed before inserting into the plug?
About 12 to 14 mm of conductor, trimmed square, with the outer jacket entering the plug by roughly 6 mm so the crimp bar grips the jacket. Keep the untwisted section under about 13 mm to protect gigabit performance.
My cable passes the tester but the PC shows 100 Mbps. Why?
Gigabit uses all four pairs; 100 Mbps uses only two. A wire in the blue or brown pair (pins 4, 5, 7, 8) is likely open or badly crimped, or the pairs are split. Re-test pin by pin, then re-crimp the suspect end.
This guide is based on the Technical Anshu RJ45 crimping video • Stuck on any step? Ask in the video comments - you will get a reply there