how is crimping RJ45 connector ?

Answer 1

The keys to good crimps are to start with good tools and taking care that the ends of the wires are trimmed evenly. Then, make only one crimping motion. The last requirement is usually met by the first since good crimping tools incorporate a ratchet assembly that forces the user to complete a full crimping motion before the crimp jaws can be returned to their detent position.

There are actually two simultaneous crimping actions performed by the crimping tool. One is to force a set of eight teeth through the insulation of the eight wires and through the wires themselves to form eight separate electrical connections. The secondary crimping forces a plastic wedge or plunger against the outer sheath that covers the four wire pairs. If the sheath is cut too far back from the ends of the wires being connected, the plastic tab of the RJ45 will simply push against the individual covering of the the wire pairs and will not firmly hold the wires in place. Be sure to trim the outer sheath of the CAT 3, 4, 5 or 5E wire just enough to allow the individual wires to extend to the end of the RJ45, while leaving the outer cable sheath to extend past the plastic tab used to hold the wiring assembly in place
Trim the outer sheath of the cable as shown. The sheath should be cut back far enough to allow the wires (with insulation) to be trimmed to even lengths and extend exactly to the end of the wire channels of the RJ45. Not too short, but just long enough to press against the end of the channels as shown. If the sheath and wires don't go into the RJ45 as shown in the side view, cut the wire back and start over. There is nothing any more frustrating than a finicky, flaky intermittent wiring connection.

Once the trimming is satisfactory and the individual wires are arranged in the proper order and flattened out for insertion into the RJ45, push the wire into the RJ45 and make sure the assembly looks like the side view drawing shown above (except for the fact that the plastic plunger and connecting blades will not be pressed down yet). Once satisfied that the assemble is ready for crimping, insert the RJ45 (with wire in place) into the jaws of the crimping tool (it should only go in one way). Next, firmly press down on the handles of the crimping tool, keeping the wire firmly pressed into the RJ45. If the correct crimping tool is used, one must continue to crimp until the process is complete. A one way ratchet device assures this.

CRIMP ONLY ONCE

If a quality tool is used, the ratchet assembly assures that the crimp was complete. Attempting to make a second crimp is more likely to bend or flatten pins or crack the plastic housing than it is to improve the crimp. If it was done correctly with a good tool, once is enough.

WHAT ACTUALLY TOOK PLACE

The crimping dies pushes two plungers down on the RJ-45 connector. One forces a plastic plug/wedge onto the cable jacket, firmly clinching it and preventing it from pulling out of the RJ45 connector. The other seats the "pins," (each with two teeth at its end) through the insulation and into the conductors of their respective wires.

TEST THE CRIMP

If properly done using quality components and tools, the connector will stay firmly in place even if pulled apart with up to 25 pounds of force. A firm pull with an average person's bare hands should not separate the cable and connector. Far better to find out that the wiring assembly won't hold up before it's put into service than to spend hours tracing a poor connection once it's in place.

Don't pull too hard when testing the crimp. If the cable is stretched, its characteristics will change. Just look at the side of the plug and see if it looks like the diagram and give it a fairly firm tug to make sure it is crimped well.

Advantages of twisted-pair cables over the older thin-wire, coaxial cables include low cost, ease of termination and reliability and permanence of the connection. RJ-45 and its ease of installation are one of the reasons coaxial cable is no longer widely used for small Ethernets. However, the larger reason is that there is no coax 100BaseTX or 1000BaseTX. The world has moved beyond 10Base2's capabilities, so coax is out and CAT 5, 5E are in. One will still find coax in older installations and this presents a problem. The problem is that there is no RJ45 equivalent to the daisy chaining of systems that was possible with coax.

After the connectors are attached, if both ends of the cable are within reach, hold them next to each other with the RJ-45 locking tabs facing away. Look through the bottom of the RJ45 connector. If the RJ45s are wired correctly, they are identical in a straight-thru cable and different in a crossover cable.

Inexpensive test tools are available that claim to test cables. However, most of these only test the cable in a static, DC voltage environment, not at 10 or 100 MHz. If an operational network is available, test the cable as part of the network and copy some large files over the cable and check the results.

If the cable doesn't work, inspect the ends again and make sure you have the right cable and that it is plugged into the correct units for the type of cable.

When many straight-through and cross-over cables are used in a system, it is a good idea to label or otherwise identify cross-over cables. One way is to use different color cable when making cross-over cables. Another is to use wiring boots such as those shown at the right. If all else fails, use a magic marker to place an "X" on both ends of cross-over cables.

Hours can be wasted testing a system only to discover that the problem was that one of the cables was a crossover cable when a straight through cable was intended.

Answer 2

How to wire Ethernet Cables:

1. Strip off about 2 inches of the cable sheath.
2. Untwist the pairs - don't untwist them beyond what you have exposed, the more untwisted cable you have the worse the problems you can run into.
3. Align the colored wires according to the diagrams above.
4. Trim all the wires to the same length, about 1/2" to 3/4" left exposed from the sheath.
5. Insert the wires into the RJ45 end - make sure each wire is fully inserted to the front of the RJ45 end and in the correct order. The sheath of the cable should extend into the RJ45 end by about 1/2" and will be held in place by the crimp.
6. Crimp the RJ45 end with the crimper tool
7. Verify the wires ended up the right order and that the wires extend to the front of the RJ45 end and make good contact with the metal contacts in the RJ45 end.
8. Cut the cable to length - make sure it is more than long enough for your needs. Remember, an end to end connection should not extend more than 100m (~328ft). Try to keep cables short, the longer the cable becomes the more it may affect performance, usually noticable as a gradual decrease in speed and increase in latency.
9. Repeat the above steps for the second RJ45 end.
10. If a cable tester is available, use it to verify the proper connectivity of the cable.

Answer 3

RJ-45 connectors are normally used in telephone and network cables. Occasionally they are used for serial network connections. When the RJ-45 connectors first came into use, they were primarily used for telephones. The great advances in technology created a need for another size connector and the RJ-45 was adapted to fit. Today there are 2 different RJ-45 connector sizes available, 1 for Cat 5 cable and 1 for Cat 6 cable. The user has to make sure they have the one suited to their job. The easiest way to tell them apart is to compare them side by side. The Cat 6 connector is larger than the Cat 5 connector. Below are instructions for crimping RJ-45 connectors to a cable.

https://www.electrikals.com/products/rc-electrical-tools/hand-crimping-tool?cnid=197&cid=693&page=1&pagesize=20