What Exactly Is A Cross Over Cable ?
What Exactly is a Cross Over Cable ?
A cross over cable is one of several ways to connect several computers together. The result is what we normally call a network.
There are actually several ways to connect multiple computers. Usually this is done through a network hub and router. However, a significant number of people and businesses accomplish the same thing by using a CAT 5e cross over cable. This directly connects two computers. As the name suggests, this cross over system has the cable wires crossed in reverse. This helps it to transmit and to receive signals.
Whereas the hub and router are a permanent networking solution, the CAT 5e cross over cable is considered a temporary solution. It's usually set up only until a hub and router can be installed.
Generally we speak of these crossovers, we're talking about Ethernet cables. The 100BASETX and 10BASET Ethernets standards both use a single wire pair for transmission in both directions. Each device's TX+line connects to the conductor tip, with the TX- line connected to the ring. This will require that each device's transmit pair be connected to the receive pair at the the other end of the device. When you have a terminal device which is connected to a hub or switch, the crossover is accomplished internally within the hub or switch. Generally, a normal straight-through cable is used for this, and each of the pins on one end of the connector is connected to its corresponding pin on the second connector.
A terminal device could be directly connected to another without using a hub or switch, however, in that case, the crossover has to be accomplished externally in the cable. Since both 100BASETX and 10BASET use pairs 2 & 3, both pairs have to be swapped within the cable. This is what is known as a cross over cable. This cross over has to also be used for connecting two hubs (or two internally crossed devices), because the internal cross overs will cancel out each other. This can also be done through use of a straight-through cable in combination with a modular cross over adapter.
Because the T568A and T568B pain / pair assignments are identical except for a swapping of pairs 2 and 3, a cross over type of cable might also be envisioned as one with a connector that follows T568A and the other T568B. This cable would work for 100BASETX or 10BASET.
Two, three or more computers can be joined as a network though their Ethernet ports. To do this correctly you must use a cross over cable. The most common one is the CAT 5e, an enhanced version of the original CAT 5.
Manufacturers of new cross overs typically make the outer coating yellow; this helps distinguish the cross over from other cables. "Cross over" will also be printed in small print on the coating.
Buying a cross over cable at the best price normally requires that you master the subject thoroughly. This is a complex field, and you must make sure you know your terminology: what is single mode, sma, a slitter, etc. How do you find the best prices on surplus cables and who are the names you can trust. Only when you've done your homework should you commit the time and money for important electronics cables.
