Crystal head practices

RJ45 network cable plug, also known as crystal head, is widely used in the connection between network cables of LAN and ADSL Broadband Internet users. Network clamp and wire measuring instrument will be used during the production process.

▲Figure: crystal head

▲Figure: Network clamp and wire Measuring Instrument

In specific applications, RJ45 plug and network cable have two connection methods (line sequence), called T568A line sequence and T568B line sequence.

Standard 568A line sequence: Green-1, green-2, orange-3, blue-4, blue-5, orange-6, brown-7, brown-8.

▲Figure: Line sequence of T568A

Standard 568B line sequence: Orange-1, orange-2, green-3, blue-4, blue-5, green-6, brown-7, brown-8

▲Figure: Line sequence of T568B

Generally, we are used to calling the twisted pair produced by both ends in the T568B line sequence as a straight line, and the twisted pair connected by one T568A and the other T568B line sequence as a cross line.

Express CONNECT: used to connect different devices, such as PCs-switches (hubs)

Crossover: used to connect to the same device. Such as: PC---PC, switch --- Switch

But now there is no need to follow this standard completely. Gigabit NICs are adaptive, that is, the same device can also use a direct connection when connecting, depending on the ID of the corresponding interface.

Production process:

The Identification Method of the RJ45 network cable plug PIN number is: Hand plug, there are 8 small gold plated tablets at one end up, there is a network cable mounted rectangular mouth at one end down, at the same time, there will be no thin plastic pin facing your eyes, from the first small gold plated tablets on the left in turn is 1st feet, 2nd feet ,... 8th feet.

Step 1: strip the wire. First, we use the cutting edge of the crimping tool to cut the length of the twisted pair cable to be used. We need to remove the gray protective layer of twisted pair wires. We can use the cutting edge of the crimping tool to cut the wire head, and then put the wire head into the special cutting edge, and hold the crimping tool with a little force to slowly rotate it, enable the cutting edge to cut out the protection rubber of twisted pair wires. In this step, it should be noted that the length of the block position of the crimping tool is usually exactly the length of the crystal head, which can effectively avoid the length of the wire. If the strip line is too long, it may not look beautiful. On the other hand, the cable cannot be stuck by the crystal head and is easy to loosen. If the strip line is too short, it cannot be completely inserted to the bottom of the crystal head due to the existence of the protective plastic layer, the connector cannot be in good contact with the core line of the network cable, affecting the quality of the line.

▲Figure: wire stripping

Step 2: cabling. We need to solve each pair of cables that are intertwined one by one. After the cables are unbundled, several groups of cables are arranged and straightened out in sequence according to the required wiring rules. During the arrangement, avoid line winding and overlapping as much as possible.

▲Figure: cabling

Step 3: cut. After we arrange the cables in sequence and straighten out the cables, we should carefully check them. Then, we cut the top of the cables by cutting the cutting edge of the crimping tool, it should be noted that the horizontal direction should be inserted during cropping, otherwise the cable length will not affect the normal contact between the cable and the crystal head. If you have stripped the protective layer too much, you can cut the long thin line here, and keep about 15mm of the remaining part of the outer protective layer, this length can be inserted into each wire slot. If the length is too long, the crosstalk will be increased because the cable Pair does not twist each other, and the cable may be removed from the crystal head because the crystal head cannot press the jacket, this may cause poor contact or even interruption of the line.

▲Figure: Cut

Step 4: plug the wire. What we need to do is to insert the cables into the crystal head. It should be noted that the crystal head has the shape of the spring piece downward, there is a pin side up, so that the end of the pin pointing away from their own direction, there is a square hole at one end of the self. At this time, the leftmost is 1st feet, the rightmost is 8th feet, and the rest are arranged in order. When inserting the need to pay attention to slowly force 8 cables at the same time along the RJ-45 head of the 8 cable slot Inserted, until the top of the slot.

▲Figure: plug-in

Step 5: after confirming the correctness, you can insert the crystal head into the 8 p groove pressure wire of the crimping tool. After inserting the crystal head, hold the tension Clamp with force. If the strength is not enough, you can press it with both hands, this press process makes all the pins protruding from the outside of the crystal head pressed into the crystal and inside the head, after the force, you can hear a slight "Snap.

▲Figure: sewing line

Step 6: test. After the network cable is ready, we can test the connectivity with the wire measuring instrument. The practice is to insert the two ends of the network cable into the measuring instrument separately. The two sets of indicators on the measuring instrument will flash. If the test is a straight-through line, the two sets of indicators on the wire measuring instrument will flash synchronously. If the two sets of indicators are not synchronized, there will be problems. If it is a crossover line, one group is in the order of 12345678, and the other group corresponds to the order of 36145278 people. Otherwise, it also indicates that there is a problem and you need to do it again!

▲Figure: Line Testing