Termination Type by Cable Use
| Cable Use | Best Termination | Why | Avoid |
|---|---|---|---|
| In-wall solid cable (permanent run) | Keystone jack at the wall; patch panel at the closet end | Designed for solid wire; punchdown is fast and consistent; serviceable without re-crimping | Hand-crimped RJ45 plugs on solid wire — solid conductors are brittle and crack with plug movement |
| Patch cable (device to jack, or port to port) | Factory pre-terminated patch cable | Stranded conductors survive bending; factory termination is more reliable than most field crimps | Field-crimping your own patch cables unless the length is non-standard |
| Outdoor camera or AP direct connection (no wall jack) | Field-terminated plug with boot and strain relief | Sometimes unavoidable for outdoor runs that terminate directly at the device | Plugs not rated for solid wire; plugs without boot (strain relief) |
| Patch panel (wiring closet) | 110-type punchdown on the back of the panel | Organizes many runs cleanly; allows re-patching without re-terminating the in-wall cable | Loose conductors; conductors punched in wrong slot |
T568A vs T568B Wiring Standard
Both are equally valid. The standard you use does not matter — what matters is using the same standard on both ends of every run. Mixing T568A on one end and T568B on the other creates a crossover cable, not a straight-through patch cable, and the link will not work.
| Pin | T568B Color (most common in US) | T568A Color |
|---|---|---|
| 1 | White/Orange | White/Green |
| 2 | Orange | Green |
| 3 | White/Green | White/Orange |
| 4 | Blue | Blue |
| 5 | White/Blue | White/Blue |
| 6 | Green | Orange |
| 7 | White/Brown | White/Brown |
| 8 | Brown | Brown |
T568B is more commonly used in the US for new installations. T568A is specified for US government work (TIA-568-C.2). Pick one and document which you used for the installation.
Keystone Jack Termination: Step by Step
Tools needed: cable stripper, punchdown tool (110-type), wire cutters, keystone jack, low-voltage mounting bracket.
- Strip the jacket: remove about 25–30mm (1 inch) of outer jacket — enough to reach the contacts without excessive untwisting. Use a dedicated cable stripper, not scissors, to avoid nicking conductors
- Keep pairs twisted: untwist each pair only as far as necessary to reach the contacts — no more than 13mm (0.5 inch) of untwisting at the termination point. Excessive untwisting increases crosstalk and reduces performance
- Seat conductors in slots: most keystone jacks have a color-coded diagram on the body showing T568A and T568B positions. Lay each conductor into its correct slot, pressing into the groove before using the punchdown tool
- Punch down each conductor: use the punchdown tool set to the correct blade orientation. The cut side of the blade should face the outside of the jack. Strike firmly — the tool seats the conductor and trims the excess in one motion
- Verify all 8 conductors: visually confirm each slot has a conductor fully seated. A missing or loose conductor will cause the link to fail or drop to 100 Mbps
- Snap the cover on the jack and seat it in the low-voltage bracket
- Test: use a wire-map tester before pushing the jack into the wall. A tester shows which pairs are connected and in correct order — catching wiring errors before they are buried in the wall
RJ45 Plug Termination: Step by Step
Only do this for stranded patch cable or unavoidable field terminations. Tools: cable stripper, RJ45 crimper, RJ45 plugs rated for the cable type.
- Strip 25–30mm of outer jacket
- Untwist all four pairs and arrange conductors in T568B or T568A order
- Trim all conductors to equal length — about 12–15mm from the jacket edge
- Slide conductors into the RJ45 plug, ensuring each conductor goes into its correct channel all the way to the front of the plug
- Verify alignment through the clear plug body before crimping
- Crimp firmly — a partial crimp leaves contacts not fully piercing the conductor insulation
- Tug gently on the cable to verify the crimp holds before use
Critical Rules That Prevent Failures
- Never untwist more than 13mm (0.5 inch) at any termination — excessive untwisting is the primary cause of Cat6 links that negotiate at 100 Mbps instead of 1 Gbps
- Use the correct plug type for cable type: solid-conductor plugs and stranded-conductor plugs have different contact designs. A stranded plug on solid cable will not make reliable contact
- Use the same standard on both ends: T568A or T568B — never mixed
- Add strain relief on any plug that will be inserted and removed — the boot protects the crimp from flexing at the cable entry
- Test before closing the wall: fix termination problems before drywall covers them
Testing After Termination
| Test Type | Tool | What It Shows | Pass Criteria |
|---|---|---|---|
| Wire map | Cheap continuity tester ($20–40) | All 8 conductors connected; correct pairing; no splits or reversals | All pairs wired correctly; no cross-pairs |
| Link negotiation | Any switch or laptop with Ethernet port | What speed the link negotiated (100 Mbps vs 1 Gbps) | 1000BASE-T (1 Gbps) for Cat5e and above |
| Throughput test | iperf3 on two devices | Actual sustained throughput across the link | 850+ Mbps on a 1 Gbps link is normal; below 500 Mbps suggests a termination problem |
| Certification | Fluke DSX or similar ($3,000+) | Full TIA-568 category compliance including insertion loss, return loss, and NEXT | Pass for the specified category (Cat5e, Cat6, Cat6A) |
Frequently Asked Questions
Should solid cable use plugs or jacks?
Fixed in-wall solid cable should terminate to keystone jacks at the room end and a patch panel at the closet or network equipment end. Use factory-made patch cables (stranded) for the flexible connection between the wall jack and the device. Putting a field-crimped RJ45 plug directly on solid cable works initially but the solid conductors are brittle — they crack internally with repeated plug insertion and become intermittent.
What is the most common termination mistake?
Untwisting pairs too far from the termination point. Many installers strip 2–3 inches of jacket and then untwist all the way back to work more easily with the conductors. Crosstalk cancellation in Cat5e, Cat6, and Cat6A depends on the pairs remaining twisted to within 13mm of the termination. Excessive untwisting is why a cable tests fine on a wire-map tester but negotiates at 100 Mbps instead of 1 Gbps. The fix is re-terminating with less untwisting.
Do I need an expensive cable certifier?
For a home installation, no. A $30 wire-map tester plus link speed and iperf3 throughput testing catches the vast majority of termination problems. A Fluke DSX certifier ($3,000+) is needed when you must prove that a run meets the full electrical specifications for Cat5e, Cat6, or Cat6A — required for professional installations, ISP handoffs, or warranty claims on the cabling. Home users who see 1 Gbps link negotiation and 900+ Mbps iperf3 throughput have successfully terminated the cable.