Crossover Cable Wiring

A technician is setting up a direct connection between two older PCs so they can communicate but not be on the corporate network.

The technician does not have access to a spare switch but does have spare Cat 6 cables, RJ-45 plugs, and a crimping tool.

The technician cuts off one end of the cable.

Which of the following should the technician do to make a crossover cable before crimping the new plug?

A.

Reverse the wires leading to pins 1 and 2

B.

Reverse the wires leading to pins 1 and 3

C.

Reverse the wires leading to pins 2 and 3

D.

Reverse the wires leading to pins 2 and 4

B.

To make a crossover cable, the technician needs to reverse the transmit and receive wires at one end of the cable. This is because when two devices communicate with each other directly, they need to send data on one set of wires while receiving data on another set of wires.

In a standard Ethernet cable, the transmit wires at one end are connected to the receive wires at the other end, and vice versa. But when connecting two devices directly, this can cause a conflict because both devices would be trying to transmit on the same wires.

Therefore, to create a crossover cable, the technician needs to switch the transmit and receive wires at one end of the cable. This can be done by reversing the wires leading to either pins 1 and 2, pins 1 and 3, pins 2 and 3, or pins 2 and 4.

Option B, which is to reverse the wires leading to pins 1 and 3, is the correct answer for this scenario. This is because pins 1 and 3 are the transmit and receive wires in the T568A standard, which is commonly used in older networking equipment.

To create a crossover cable using this method, the technician should follow these steps:

1. Cut off one end of the cable using the crimping tool.
2. Untwist the wires and separate them into pairs. The pairs should be orange/white and orange, green/white and blue, blue/white and green, and brown/white and brown.
3. Reverse the wires in the orange and green pairs. Specifically, swap the wire in pin 1 with the wire in pin 3 for both pairs.
4. Re-arrange the wires in the correct order for the RJ-45 plug according to the T568A or T568B standard, depending on which one is used by the devices being connected.
5. Use the crimping tool to attach the new RJ-45 plug to the cable, making sure to follow proper crimping procedures to ensure a good connection.

Once the crossover cable is made, the technician can connect the two PCs using the cable and they should be able to communicate with each other without being on the corporate network.